Chapter -1.5 "Forces" - Short Questions
"Forces" - Short Questions
1. What is a force?
A force is a push or a pull that can change the motion, size, or shape of an object.
2. What is meant by deformation?
Deformation is a change in the size or shape of an object caused by a force.
3. Give one example of a force changing the size of an object.
Stretching a rubber band makes it longer.
4. Give one example of a force changing the shape of an object.
Bending a ruler causes it to curve.
5. What is tension?
Tension is a stretching force that pulls an object apart.
6. What is compression?
Compression is a force that pushes an object together, making it shorter.
7. What happens to particles in a material during stretching?
The particles move further apart.
8. What happens to particles in a material during compression?
The particles are pushed closer together.
9. What is bending?
Bending occurs when one part of an object is in tension and another part is in compression.
10. What is torsion?
Torsion is a twisting force applied to an object.
11. Define elastic deformation.
Elastic deformation is when an object returns to its original shape after the force is removed.
12. Give one example of elastic deformation.
A spring returning to its original length after being stretched.
13. Define plastic deformation.
Plastic deformation is when an object does not return to its original shape after the force is removed.
14. Give one example of plastic deformation.
A bent paperclip that stays bent.
15. What is the elastic limit?
The elastic limit is the maximum force an object can experience and still return to its original shape.
16. What happens if the elastic limit is exceeded?
The object undergoes permanent, or plastic, deformation.
17. State one factor that affects the amount of deformation.
The magnitude of the force.
18. How does the size of a force affect deformation?
A larger force generally causes greater deformation.
19. How does material type affect deformation?
Different materials deform differently depending on their internal structure and bonding.
20. Why do engineers need to understand deformation?
To design structures that can withstand forces without permanent damage or failure.
21. What is a load–extension graph?
A load–extension graph shows the relationship between the applied force (load) and the extension of an elastic object.
22. What is meant by load?
Load is the force applied to an object, usually measured in newtons (N).
23. How is load calculated?
Load = mass × gravitational field strength (F = mg).
24. What is extension?
Extension is the increase in length of an object when a force is applied.
25. How is extension calculated?
Extension = stretched length − original length.
26. What is an elastic solid?
An elastic solid is a material that returns to its original length when the load is removed, provided the elastic limit is not exceeded.
27. State Hooke’s law.
Hooke’s law states that load is directly proportional to extension, provided the elastic limit is not exceeded.
28. Write Hooke’s law as an equation.
F = kx
where F is force, k is the spring constant, and x is extension.
29. What does the straight-line region of a load–extension graph show?
It shows that load is directly proportional to extension.
30. What does the gradient of a load–extension graph represent?
The gradient represents the stiffness (spring constant) of the object.
31. What does a steeper gradient indicate?
A steeper gradient indicates a stiffer material.
32. What is the limit of proportionality?
The limit of proportionality is the point where the graph stops being a straight line and begins to curve.
33. What happens beyond the limit of proportionality?
Extension is no longer directly proportional to load.
34. What is the elastic limit?
The elastic limit is the maximum load at which an object returns to its original length when unloaded.
35. What happens if the elastic limit is exceeded?
Permanent, or plastic, deformation occurs.
36. What is plastic deformation?
Plastic deformation is permanent change in length after the load is removed.
37. What happens to the unloading curve after plastic deformation?
The unloading line does not return to the origin, showing permanent extension.
38. Which axis should extension be plotted on?
Extension is plotted on the horizontal axis.
39. Which axis should load be plotted on?
Load is plotted on the vertical axis.
40. Why must loads be added gradually in the experiment?
To avoid sudden stretching and exceeding the elastic limit.
41. Why is a pointer used in the experiment?
To reduce parallax error when reading measurements.
42. State one safety precaution in a load–extension experiment.
Wear safety goggles in case the spring or wire snaps.
43. What happens to the graph after the limit of proportionality?
The graph curves upwards.
44. How can stiffness be compared using graphs?
By comparing the gradients of the straight-line sections.
45. Why must the original length be measured first?
To calculate the extension accurately.
46. What unit is used for extension?
Metres (m).
47. What unit is used for load?
Newtons (N).
48. Why should appropriate scales be chosen when plotting the graph?
To ensure the graph uses most of the paper and is easy to interpret.
49. Give one real-life application of load–extension graphs.
Testing materials used in bridges and buildings.
50. Why is understanding elastic behavior important in engineering?
To ensure materials do not permanently deform or fail under normal loads.
51. What are collinear forces?
Collinear forces are forces that act along the same straight line.
52. What is meant by resultant force?
The resultant force is the single force that has the same effect as all the forces acting together.
53. What is the unit of resultant force?
The newton (N).
54. How do you find the resultant when forces act in the same direction?
Add their magnitudes.
55. Two forces of 10 N and 15 N act to the right. What is the resultant?
25 N to the right.
56. How do you find the resultant when forces act in opposite directions?
Subtract the smaller force from the larger force.
57. A 40 N force acts right and a 25 N force acts left. What is the resultant?
15 N to the right.
58. What are balanced forces?
Balanced forces are equal in magnitude and opposite in direction.
59. What is the resultant force when forces are balanced?
Zero newtons.
60. What does a zero resultant force mean?
The object is either at rest or moving at constant velocity.
61. Does zero resultant force mean no forces are acting?
No, it means the forces cancel each other out.
62. If the resultant force is not zero, what happens to the object?
It accelerates in the direction of the resultant force.
63. In which direction does acceleration occur?
In the direction of the resultant force.
64. A car has a driving force of 800 N forward and 800 N resistive force backward. What is the resultant?
0 N.
65. What will happen to the car in Question 64?
It moves at constant speed.
66. What is a free-body diagram?
A diagram showing all the forces acting on an object using arrows.
67. What does the length of an arrow in a force diagram represent?
The magnitude of the force.
68. Why is direction important when calculating resultants?
Because forces in opposite directions reduce each other.
69. How can sign convention help in calculations?
One direction is taken as positive and the opposite as negative, making addition easier.
70. If right is positive, how would you write a 12 N force to the left?
−12 N.
71. Calculate the resultant: +20 N and −8 N.
+12 N (12 N in the positive direction).
72. Three forces act on an object: 5 N right, 15 N right, 12 N left. What is the resultant?
8 N to the right.
73. What is equilibrium?
A state where the resultant force is zero.
74. Can an object in equilibrium be moving?
Yes, it can move at constant speed.
75. Give one example of vertical collinear forces.
Weight acting downward and normal reaction acting upward.
76. Give one example of horizontal collinear forces.
Driving force forward and friction backward.
77. What happens if the forward force is greater than friction?
The object accelerates forward.
78. In a tug-of-war, one team pulls with 500 N and the other with 450 N. What is the resultant?
50 N in the direction of the stronger team.
79. Why is it important to include friction when calculating resultants?
Because friction affects the net force and motion.
80. What is a common mistake when finding resultant forces?
Ignoring direction and simply adding magnitudes.
81. State Newton’s First Law of Motion.
An object remains at rest or continues moving at constant speed in a straight line unless acted on by a resultant force.
82. What is meant by constant velocity?
Constant velocity means constant speed in a straight line.
83. When does an object remain at rest?
When the resultant force acting on it is zero.
84. What happens when the resultant force on an object is zero?
The object remains at rest or moves with constant velocity.
85. What is equilibrium?
Equilibrium is the state in which the resultant force on an object is zero.
86. What is static equilibrium?
Static equilibrium occurs when an object is at rest and the resultant force is zero.
87. What is dynamic equilibrium?
Dynamic equilibrium occurs when an object moves at constant velocity and the resultant force is zero.
88. Is a force needed to keep an object moving at constant speed?
No, a force is only needed to change motion.
89. What causes a moving object to slow down on Earth?
Friction or air resistance.
90. What is inertia?
Inertia is the tendency of an object to resist changes in its motion.
91. Which object has more inertia: a truck or a bicycle?
A truck, because it has greater mass.
92. How does mass affect inertia?
Greater mass means greater inertia.
93. Why do passengers move forward when a bus stops suddenly?
Due to inertia, their bodies continue moving forward.
94. What force stops passengers from moving forward in a car?
The seatbelt provides the stopping force.
95. Why does a hockey puck slide for a long distance on ice?
Because friction is very small.
96. Why does a ball eventually stop rolling on the ground?
Friction acts opposite to its motion.
97. What type of force is needed to change an object’s speed?
A non-zero resultant force.
98. What type of force is needed to change an object’s direction?
A non-zero resultant force.
99. Can an object move if no forces are acting on it?
Yes, it can move at constant velocity.
100. Does zero resultant force mean zero motion?
No, the object may still be moving at constant speed.
101. Why does a spacecraft continue moving in space without engines on?
Because there is almost no friction and no resultant force acting on it.
102. What must happen for an object at rest to start moving?
A non-zero resultant force must act on it.
103. Give one example of balanced forces.
Weight downward and normal reaction upward on a book resting on a table.
104. What happens when driving force equals frictional force?
The object moves at constant speed.
105. Why is it harder to push a heavy object than a light one?
Because the heavier object has greater inertia.
106. What is a common misconception about force and motion?
That a force is needed to keep an object moving.
107. What actually requires a continuous force in everyday motion?
Overcoming friction and air resistance.
108. What happens if friction did not exist?
Objects would continue moving indefinitely once set in motion.
109. Why are air tracks used in experiments?
To reduce friction and demonstrate motion with nearly zero resultant force.
110. Why are seatbelts important in vehicles?
They provide the force needed to stop passengers safely when the car stops suddenly.
111. What is velocity?
Velocity is speed in a given direction.
112. Is velocity a scalar or vector quantity?
Vector quantity.
113. What two things does velocity include?
Speed and direction.
114. What is meant by a change in velocity?
A change in speed, direction, or both.
115. What is required to change the velocity of an object?
A non-zero resultant force.
116. What happens to velocity when the resultant force is zero?
Velocity remains constant.
117. What is acceleration?
Acceleration is the rate of change of velocity.
118. If a car speeds up, has its velocity changed?
Yes, because its speed has changed.
119. If a car turns at constant speed, has its velocity changed?
Yes, because its direction has changed.
120. When a force acts in the same direction as motion, what happens?
The object speeds up.
121. When a force acts opposite to the direction of motion, what happens?
The object slows down.
122. What is deceleration?
Deceleration is a decrease in speed.
123. When a force acts at right angles to motion, what changes?
The direction changes.
124. Does circular motion involve a change in velocity?
Yes, because the direction is constantly changing.
125. In circular motion, where does the resultant force act?
Towards the center of the circle.
126. What provides the centripetal force for a car turning a corner?
Friction between the tyres and the road.
127. A ball thrown upward slows down. What causes this?
The downward force of gravity.
128. When balanced forces act on a moving object, what happens?
It continues at constant speed in a straight line.
129. What type of line on a velocity–time graph shows constant velocity?
A horizontal line.
130. What type of line on a velocity–time graph shows acceleration?
A sloping line.
131. What does a steeper slope on a velocity–time graph indicate?
Greater acceleration.
132. If a cyclist turns left at constant speed, has acceleration occurred?
Yes, because the direction has changed.
133. What force slows a rolling football on the ground?
Friction.
134. Why does a spacecraft change direction when orbiting Earth?
Gravity provides the inward force.
135. If a force acts at an angle to motion, what may change?
Both speed and direction.
136. Why are seatbelts important during sudden stops?
They apply a force to reduce passengers’ velocity safely.
137. Can velocity change without speed changing?
Yes, if the direction changes.
138. Can speed change without direction changing?
Yes, if the object speeds up or slows down in a straight line.
139. What happens if the driving force on a car is greater than resistive forces?
The car accelerates forward.
140. Why is understanding velocity important in physics?
Because motion depends on both speed and direction, and forces change velocity.
141. What is solid friction?
Solid friction is the force between two solid surfaces in contact that opposes motion or attempted motion.
142. In which direction does solid friction act?
Opposite to the direction of motion or attempted motion.
143. Does solid friction act without contact between surfaces?
No, it only acts when surfaces are in contact.
144. Why does friction exist between surfaces that appear smooth?
Because of microscopic irregularities and molecular attraction.
145. What are the tiny bumps on surfaces called?
Asperities.
146. What are the two main types of solid friction?
Static friction and kinetic (sliding) friction.
147. What is static friction?
Friction that prevents motion when surfaces are in contact but not moving.
148. What is kinetic friction?
Friction that acts when two surfaces are sliding over each other.
149. Which is usually greater: maximum static friction or kinetic friction?
Maximum static friction is usually greater.
150. Why is it harder to start moving a heavy box than to keep it moving?
Because static friction is greater than kinetic friction.
151. What happens if the applied force is less than static friction?
The object does not move.
152. What happens if the applied force is greater than friction?
The object accelerates.
153. Why does a sliding book eventually stop?
Kinetic friction slows it down.
154. What form of energy is produced when friction acts?
Thermal energy (heat).
155. Why do your hands feel warm when rubbed together?
Friction converts kinetic energy into heat.
156. Why do car brakes become hot?
Friction converts kinetic energy into heat during braking.
157. What happens to kinetic energy when friction acts?
It is converted into thermal energy.
158. Does friction destroy energy?
No, it converts energy into heat.
159. How does surface roughness affect friction?
Rougher surfaces produce greater friction.
160. How does weight affect friction?
Greater weight increases friction.
161. Why is it harder to push a heavy object than a light one?
Because the force pressing the surfaces together is greater.
162. Give one example where friction is useful.
Walking.
163. Why is friction necessary for walking?
It prevents slipping between shoes and the ground.
164. Give one disadvantage of friction.
It causes wear and tear on surfaces.
165. How does lubrication reduce friction?
It creates a thin layer between surfaces, reducing direct contact.
166. Why are tyres designed with treads?
To increase friction with the road.
167. Why are ball bearings used in machines?
To reduce sliding friction by replacing it with rolling friction.
168. What happens to machine efficiency when friction is high?
Efficiency decreases due to energy loss as heat.
169. Does friction act when an object is at rest?
Yes, static friction can act.
170. Why is friction important in braking systems?
It reduces velocity by converting kinetic energy into heat.
171. What is drag in liquids?
Drag is the frictional force that opposes motion of an object moving through a liquid.
172. In which direction does drag act?
Opposite to the direction of motion.
173. Does drag act when an object is stationary in a liquid?
No, drag only acts when there is relative motion.
174. What type of force is drag?
A resistive force.
175. What must an object do to move through a liquid?
Push liquid particles out of the way.
176. Name two main causes of drag in liquids.
Viscous resistance and pressure differences.
177. What is viscosity?
Viscosity is a measure of a liquid’s resistance to flow.
178. Which produces more drag: water or honey?
Honey, because it has higher viscosity.
179. How does speed affect drag?
As speed increases, drag increases.
180. Why does swimming become harder at higher speeds?
Because drag increases rapidly with speed.
181. How does shape affect drag?
Streamlined shapes reduce drag.
182. What type of shape reduces drag in liquids?
A smooth, streamlined shape.
183. Why do fish have streamlined bodies?
To reduce drag and move efficiently through water.
184. How does surface area affect drag?
Larger surface area increases drag.
185. Why does a flat board experience more drag than a thin rod?
Because it has a larger surface area facing the motion.
186. What happens to an object moving through liquid if no driving force acts?
It slows down due to drag.
187. Name three forces acting on an object falling through a liquid.
Weight, upthrust, and drag.
188. In which direction does drag act on a falling object in liquid?
Upward.
189. What is terminal velocity?
The constant maximum speed reached when forces are balanced.
190. What condition must be satisfied at terminal velocity?
Weight equals drag plus upthrust.
191. What is the resultant force at terminal velocity?
Zero.
192. Does acceleration occur at terminal velocity?
No, acceleration is zero.
193. Why is terminal velocity lower in liquids than in air?
Because liquids produce greater drag.
194. What happens to drag as a falling object speeds up in liquid?
Drag increases.
195. Why do submarines have streamlined shapes?
To reduce drag and improve efficiency.
196. How can drag be reduced in liquids?
By streamlining, polishing surfaces, and reducing speed.
197. Give one example where drag is useful.
Sea anchors stabilizing boats.
198. What force limits the speed of a rising air bubble in water?
Drag.
199. Why does a toy boat slow down after being pushed?
Drag from the water opposes its motion.
200. Is drag a type of friction?
Yes, drag is friction in fluids.
201. What is air resistance?
Air resistance is the frictional force that opposes motion of an object moving through air.
202. In which direction does air resistance act?
Opposite to the direction of motion.
203. Does air resistance act on a stationary object?
No, it only acts when there is relative motion.
204. What causes air resistance?
Collisions with air molecules and pressure differences around the object.
205. Why does air have resistance even though it is invisible?
Because air has mass and is made of molecules.
206. How does speed affect air resistance?
Air resistance increases as speed increases.
207. Why is it harder to cycle at high speeds?
Because air resistance increases rapidly with speed.
208. How does shape affect air resistance?
Streamlined shapes reduce air resistance.
209. What is a streamlined shape?
A smooth shape that allows air to flow easily around it.
210. Why are airplanes designed with streamlined bodies?
To reduce air resistance and improve efficiency.
211. How does surface area affect air resistance?
Greater surface area increases air resistance.
212. Why does a flat sheet of paper fall slower than a crumpled one?
Because it has a larger surface area and experiences more air resistance.
213. What force acts upward on a falling object in air?
Air resistance.
214. What two main forces act on a falling object in air?
Weight and air resistance.
215. What happens to air resistance as a falling object speeds up?
Air resistance increases.
216. What is terminal velocity?
The constant maximum speed reached when air resistance equals weight.
217. What is the resultant force at terminal velocity?
Zero.
218. Does a falling object accelerate at terminal velocity?
No, acceleration is zero.
219. Why does a skydiver fall slower after opening a parachute?
Because surface area increases, increasing air resistance.
220. Why does a stone fall faster than a feather in air?
Because air resistance affects the feather more due to its shape and surface area.
221. Do heavier objects fall faster in a vacuum?
No, they fall at the same rate.
222. How does air resistance affect vehicle fuel consumption?
It increases fuel consumption at high speeds.
223. Why do racing cyclists bend low over their handlebars?
To reduce air resistance.
224. What happens to kinetic energy when work is done against air resistance?
It is transferred to thermal energy and air motion.
225. Give one advantage of air resistance.
It allows parachutes to slow descent safely.
226. Give one disadvantage of air resistance.
It reduces efficiency and increases fuel use.
227. Why do shuttlecocks slow down quickly in badminton?
They are designed to have high air resistance.
228. Does air resistance act at low speeds?
Yes, but it is much smaller.
229. How can air resistance be reduced?
By streamlining, smoothing surfaces, and reducing exposed area.
230. Why is understanding air resistance important in physics?
Because it explains motion of falling objects, vehicles, and aircraft.
231. What is the spring constant?
The spring constant is the force per unit extension of a spring.
232. What symbol is used for spring constant?
k
233. State the equation for spring constant.
k = F / x
234. What does F represent in the equation k = F / x?
Force in newtons (N).
235. What does x represent in the equation k = F / x?
Extension in metres (m).
236. What is the SI unit of spring constant?
Newtons per metre (N/m).
237. What does a large value of k indicate?
The spring is stiff.
238. What does a small value of k indicate?
The spring is soft and stretches easily.
239. Rearrange k = F / x to find F.
F = kx
240. Rearrange k = F / x to find x.
x = F / k
241. A force of 12 N produces an extension of 0.03 m. Calculate k.
k = 12 / 0.03 = 400 N/m
242. A spring has k = 250 N/m and is stretched by 0.04 m. Find F.
F = 250 × 0.04 = 10 N
243. A spring has k = 500 N/m and a force of 20 N is applied. Find x.
x = 20 / 500 = 0.04 m
244. What is extension?
Extension is the increase in length of a spring.
245. How is extension calculated?
Extension = stretched length − original length.
246. In which unit must extension be used in calculations?
Metres (m).
247. What happens to extension if the applied force is doubled (within elastic limit)?
Extension also doubles.
248. Which law describes the proportional relationship between force and extension?
Hooke’s law.
249. When does Hooke’s law apply?
When the elastic limit is not exceeded.
250. What happens if the elastic limit is exceeded?
The spring no longer obeys Hooke’s law and may deform permanently.
251. On a force–extension graph, what does the gradient represent?
The spring constant.
252. If the graph is steeper, what does it mean about the spring?
It has a larger spring constant.
253. If two springs have k values of 300 N/m and 150 N/m, which is stiffer?
The spring with 300 N/m.
254. If the same force is applied to two springs, which stretches more: higher k or lower k?
The spring with lower k.
255. What happens to the spring constant within the elastic limit?
It remains constant.
256. Does the spring constant depend on the material of the spring?
Yes.
257. Does the spring constant depend on the thickness of the spring wire?
Yes.
258. How can the spring constant be found experimentally?
From the gradient of a force–extension graph.
259. Why must loads be added gradually in a spring experiment?
To avoid exceeding the elastic limit.
260. Why is understanding spring constant important?
It allows prediction of how a spring behaves under different forces.
261. What is the limit of proportionality?
It is the point on a load–extension graph beyond which extension is no longer directly proportional to load.
262. On which type of graph is the limit of proportionality identified?
A load–extension graph.
263. What does proportional mean in physics?
Two quantities increase or decrease at the same rate.
264. How does a proportional relationship appear on a graph?
As a straight line through the origin.
265. In a load–extension graph, which axis shows load?
The vertical axis.
266. In a load–extension graph, which axis shows extension?
The horizontal axis.
267. What law applies in the straight-line region of the graph?
Hooke’s law.
268. Up to what point does Hooke’s law apply?
Up to the limit of proportionality.
269. What happens to the graph beyond the limit of proportionality?
It begins to curve.
270. What does a curved graph indicate about the relationship between load and extension?
They are no longer directly proportional.
271. How can you identify the limit of proportionality on a graph?
It is where the straight line ends and the curve begins.
272. Does the graph pass through the origin in the proportional region?
Yes.
273. What happens to the gradient in the straight-line region?
It remains constant.
274. What does a constant gradient indicate?
A constant spring constant.
275. If doubling the load doubles the extension, what does this show?
The quantities are proportional.
276. What happens to extension beyond the limit of proportionality?
It increases more rapidly than load.
277. Is the limit of proportionality necessarily the point where the spring breaks?
No.
278. Does the limit of proportionality mark permanent deformation?
Not necessarily.
279. Why must loads be added gradually in experiments?
To observe the straight-line region clearly.
280. Why should measurements be taken carefully near the limit of proportionality?
To identify where the graph begins to curve.
281. What shape is the graph below the limit of proportionality?
A straight line.
282. What shape is the graph above the limit of proportionality?
A curve.
283. Why is the limit of proportionality important?
It shows the maximum load for which Hooke’s law applies.
284. Can calculations using F = kx be used beyond the limit of proportionality?
No.
285. What does it mean if the graph no longer passes through the origin?
The relationship is not proportional.
286. How is extension calculated?
Extension = stretched length − original length.
287. In which unit should extension be expressed in calculations?
Metres (m).
288. What happens if you exceed the proportional region in experiments?
Results no longer follow Hooke’s law.
289. Is the limit of proportionality always clearly marked?
No, it must be identified where the graph starts to deviate from a straight line.
290. What is the key feature used to identify the limit of proportionality?
The end of the straight-line section of the graph.
291. State the equation linking force, mass, and acceleration.
F = ma
292. What does F represent in F = ma?
Resultant force in newtons (N).
293. What does m represent in F = ma?
Mass in kilograms (kg).
294. What does a represent in F = ma?
Acceleration in metres per second squared (m/s²).
295. What is the unit of force?
Newton (N).
296. What is the unit of mass?
Kilogram (kg).
297. What is the unit of acceleration?
Metres per second squared (m/s²).
298. What type of force must be used in F = ma?
The resultant force.
299. Rearrange F = ma to find acceleration.
a = F / m
300. Rearrange F = ma to find mass.
m = F / a
301. If the force increases and mass stays constant, what happens to acceleration?
Acceleration increases.
302. If mass increases and force stays constant, what happens to acceleration?
Acceleration decreases.
303. In which direction does acceleration act?
In the same direction as the resultant force.
304. A force of 15 N acts on a 3 kg object. Find the acceleration.
a = 15 / 3 = 5 m/s²
305. A 4 kg object accelerates at 2 m/s². Find the force.
F = 4 × 2 = 8 N
306. A force of 18 N produces an acceleration of 3 m/s². Find the mass.
m = 18 / 3 = 6 kg
307. What happens if the resultant force is zero?
Acceleration is zero.
308. If acceleration is zero, what can be said about motion?
The object is at rest or moving at constant velocity.
309. Does acceleration always mean speeding up?
No, it can also mean slowing down or changing direction.
310. If a force acts opposite to motion, what happens?
The object decelerates.
311. When a car accelerates forward, in which direction is the acceleration?
Forward.
312. When brakes are applied, in which direction is the acceleration?
Opposite to the direction of motion.
313. Why is it harder to accelerate a truck than a bicycle with the same force?
Because the truck has greater mass.
314. If a 2 kg object experiences a 10 N force, what is its acceleration?
a = 10 / 2 = 5 m/s²
315. What happens to acceleration if mass is doubled but force remains the same?
Acceleration halves.
316. What happens to acceleration if force is doubled but mass remains the same?
Acceleration doubles.
317. Can acceleration occur if speed stays constant?
Yes, if direction changes.
318. What causes acceleration in circular motion?
A resultant force towards the center.
319. What must be true about mass when using F = ma in this syllabus?
Mass must remain constant.
320. Why is F = ma important in physics?
It explains how forces change motion.
321. State Newton’s First Law of Motion.
An object remains at rest or moves at constant speed in a straight line unless acted on by a resultant force.
322. What is another name for Newton’s First Law?
The law of inertia.
323. What is inertia?
The tendency of an object to resist changes in its motion.
324. Which object has greater inertia: a 2 kg mass or a 10 kg mass?
The 10 kg mass.
325. What must be true for an object to remain at rest?
The resultant force must be zero.
326. What must be true for an object to move at constant velocity?
The resultant force must be zero.
327. What happens if the forces on an object are balanced?
Acceleration is zero.
328. Why does a rolling ball eventually stop on the ground?
Because friction provides a resultant force opposite to motion.
329. State Newton’s Second Law of Motion.
The acceleration of an object is directly proportional to the resultant force and inversely proportional to its mass.
330. Write Newton’s Second Law as an equation.
F = ma
331. In F = ma, what type of force must be used?
The resultant force.
332. If the force increases and mass stays the same, what happens to acceleration?
Acceleration increases.
333. If mass increases and force stays the same, what happens to acceleration?
Acceleration decreases.
334. In which direction does acceleration occur?
In the same direction as the resultant force.
335. What happens if a force acts opposite to motion?
The object decelerates.
336. Can acceleration occur if speed remains constant?
Yes, if direction changes.
337. What causes a car to accelerate forward?
A forward resultant force.
338. What happens when braking force is greater than driving force?
The car slows down.
339. State Newton’s Third Law of Motion.
When two objects interact, they exert equal and opposite forces on each other.
340. What are action–reaction forces?
Pairs of equal and opposite forces acting on different objects.
341. Do action–reaction forces cancel each other out?
No, because they act on different objects.
342. When you push a wall, what does the wall do?
It pushes back with an equal and opposite force.
343. When walking, which force moves you forward?
The forward force exerted by the ground on your foot.
344. How does a rocket move upward?
Gases expelled downward push the rocket upward.
345. What causes recoil in a gun?
The bullet exerts an equal and opposite force on the gun.
346. Why does a heavy gun recoil less than a light bullet moves forward?
Because the gun has much greater mass.
347. Which law explains balanced forces?
Newton’s First Law.
348. Which law explains how force causes acceleration?
Newton’s Second Law.
349. Which law explains interaction forces?
Newton’s Third Law.
350. Why are Newton’s laws important in physics?
They explain how forces affect motion in everyday life and engineering.
Thank You!
Sana Shariq
For revision visit
https://youtu.be/pUPIkAcvmDo
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