Extra 40 MCQ (Multiple Choice Questions) with Answers from the chapter:9 Force and Laws of Motion chapter of Class 9 CBSE Science:-
1. Which of the following is a unit of force?
a) Joule
b) Newton
c) Watt
d) Pascal
Answer:
b) Newton
2. Newton’s First Law of Motion is also known as:
a) Law of acceleration
b) Law of inertia
c) Law of momentum
d) Law of action and reaction
Answer:
b) Law of inertia
3. The inertia of an object depends on:
a) Volume
b) Mass
c) Density
d) Shape
Answer:
b) Mass
4. The SI unit of momentum is:
a) kg m²/s²
b) kg m/s
c) m/s²
d) N m
Answer:
b) kg m/s
5. A passenger standing in a bus falls forward when the bus suddenly stops. This is due to:
a) Newton’s Second Law
b) Newton’s Third Law
c) Inertia of motion
d) Inertia of rest
Answer:
c) Inertia of motion
6. Which of the following statements is true about Newton’s Second Law of Motion?
a) Force = Mass × Acceleration
b) Momentum = Mass × Velocity
c) Every action has an equal and opposite reaction
d) Force is inversely proportional to acceleration
Answer:
a) Force = Mass × Acceleration
7. What is the force required to accelerate a 10 kg object at 2 m/s²?
a) 5 N
b) 10 N
c) 20 N
d) 40 N
Answer:
c) 20 N
8. The Newton’s Second Law of Motion gives us the definition of:
a) Acceleration
b) Force
c) Momentum
d) Energy
Answer:
b) Force
9. What happens when a force is applied to a moving object in the same direction as its motion?
a) Speed decreases
b) Speed remains constant
c) Speed increases
d) The object stops
Answer:
c) Speed increases
10. A ball is dropped from a height. It bounces back after hitting the ground. Which law of motion explains this?
a) First Law
b) Second Law
c) Third Law
d) Law of Conservation of Energy
Answer:
c) Third Law
11. Which of the following is an example of Newton’s Third Law?
a) A book resting on a table
b) A car accelerating on the road
c) A rocket launch
d) A ball rolling on the ground
Answer:
c) A rocket launch
12. If the mass of a body is doubled, what happens to its inertia?
a) Remains the same
b) Becomes half
c) Doubles
d) Becomes zero
Answer:
c) Doubles
13. A person sitting inside a moving car suddenly jerks backward when the car stops. This is due to:
a) Inertia of motion
b) Inertia of rest
c) Momentum
d) Acceleration
Answer:
a) Inertia of motion
14. The rate of change of momentum is equal to:
a) Velocity
b) Acceleration
c) Force
d) Work
Answer:
c) Force
15. A football hits a wall and bounces back. This is an example of:
a) Newton’s First Law
b) Newton’s Second Law
c) Newton’s Third Law
d) Law of Gravitation
Answer:
c) Newton’s Third Law
16. A man pushes a wall but the wall does not move. This is an example of:
a) Balanced force
b) Unbalanced force
c) Gravitational force
d) Reaction force
Answer:
a) Balanced force
17. The relation between impulse and momentum is:
a) Impulse = Change in momentum
b) Impulse = Mass × Acceleration
c) Impulse = Velocity × Time
d) Impulse = Mass × Distance
Answer:
a) Impulse = Change in momentum
18. A gun recoils when fired. This is an example of:
a) Newton’s First Law
b) Newton’s Second Law
c) Newton’s Third Law
d) Law of Conservation of Energy
Answer:
c) Newton’s Third Law
19. A bicycle comes to rest after a certain distance when we stop pedalling. This is due to:
a) Gravitational force
b) Inertia
c) Friction
d) Acceleration
Answer:
c) Friction
20. A force of 50 N is applied on a 5 kg object. What is the acceleration?
a) 5 m/s²
b) 10 m/s²
c) 15 m/s²
d) 20 m/s²
Answer:
b) 10 m/s²
21. What is the unit of force?
a) Newton
b) Pascal
c) Joule
d) Watt
Answer:
a) Newton
22. The force that opposes motion is called:
a) Gravitational force
b) Friction
c) Magnetic force
d) Electrostatic force
Answer:
b) Friction
23. What is the SI unit of inertia?
a) Newton
b) Joule
c) Kilogram
d) No unit
Answer:
d) No unit (Inertia depends on mass)
24. A moving bus stops suddenly and passengers fall forward due to:
a) Inertia of motion
b) Inertia of rest
c) Newton’s Second Law
d) Acceleration
Answer:
a) Inertia of motion
25. Which law explains the working of a rocket?
a) Newton’s First Law
b) Newton’s Second Law
c) Newton’s Third Law
d) Law of Universal Gravitation
Answer:
c) Newton’s Third Law
26. If action force = 50 N, the reaction force will be:
a) 100 N
b) 25 N
c) 50 N in opposite direction
d) Zero
Answer:
c) 50 N in opposite direction
27. The property of an object to resist a change in motion is called:
a) Acceleration
b) Momentum
c) Inertia
d) Force
Answer:
c) Inertia
28. If an object is in equilibrium, the net force acting on it is:
a) Maximum
b) Zero
c) Equal to acceleration
d) Depends on the object’s mass
Answer:
b) Zero
29. What causes a car to slow down when brakes are applied?
a) Inertia
b) Friction
c) Momentum
d) Acceleration
Answer:
b) Friction
30. An object at rest will remain at rest unless:
a) It moves on its own
b) An external force is applied
c) The mass is increased
d) The temperature increases
Answer:
b) An external force is applied
31. Action and reaction forces act on:
a) The same object
b) Different objects
c) Both the same and different objects
d) Only in circular motion
Answer:
b) Different objects
32. Momentum is a product of:
a) Mass and velocity
b) Force and acceleration
c) Distance and time
d) Energy and power
Answer:
a) Mass and velocity
33. A cricketer lowers his hands while catching a ball to:
a) Increase the force on his hands
b) Decrease the time of impact
c) Reduce the force by increasing the time of impact
d) Increase the momentum of the ball
Answer:
c) Reduce the force by increasing the time of impact
34. What is the force of gravity acting on a 10 kg mass?
a) 10 N
b) 98 N
c) 100 N
d) 9.8 N
Answer:
b) 98 N (Using F=mg=10×9.8F = mg = 10 \times 9.8F=mg=10×9.8)
35. The acceleration of a freely falling object is:
a) 0 m/s²
b) 9.8 m/s²
c) 4.9 m/s²
d) 98 m/s²
Answer:
b) 9.8 m/s²
36. A force of 100 N acts on a 20 kg mass. What is the acceleration?
a) 5 m/s²
b) 10 m/s²
c) 15 m/s²
d) 20 m/s²
Answer:
b) 5 m/s² (Using a=F
/
m=100
/
20
)
37. Why do passengers lurch backward in a bus when it starts suddenly?
a) Due to momentum
b) Due to inertia of rest
c) Due to friction
d) Due to gravitational force
Answer:
b) Due to inertia of rest
38. What type of force is responsible for wearing out of tires?
a) Gravitational force
b) Magnetic force
c) Frictional force
d) Electrostatic force
Answer:
c) Frictional force
39. What happens to momentum if velocity doubles?
a) It becomes half
b) It remains the same
c) It doubles
d) It quadruples
Answer:
c) It doubles (Since momentum p=
mvp
=
mvp
=mv)
40. Why is it more difficult to stop a moving truck than a moving bike?
a) Because the truck has more acceleration
b) Because the truck has greater mass and momentum
c) Because the truck is moving faster
d) Because the bike has more force
Answer:
b) Because the truck has greater mass and momentum
