Q.1 A body of mass 10 kg is at rest. A force of 20 N is applied on it. What is the acceleration produced?
0.5 m/s²
2 m/s²
20 m/s²
200 m/s²
Explanation - Using Newton's second law, F = ma => a = F/m = 20/10 = 2 m/s².
Correct answer is: 2 m/s²
Q.2 Which of the following is an example of Newton's third law of motion?
A book resting on a table
A rocket launching into space
A car accelerating forward
A stationary ball
Explanation - Newton's third law states that for every action, there is an equal and opposite reaction. The rocket pushes gases backward, and the gases push the rocket forward.
Correct answer is: A rocket launching into space
Q.3 An object continues to move with constant velocity when:
A net force acts on it
No net force acts on it
Friction acts on it
It is thrown upward
Explanation - According to Newton's first law, if no net force acts on an object, it will continue in its state of rest or uniform motion.
Correct answer is: No net force acts on it
Q.4 A 5 kg object is moving with acceleration 4 m/s². What is the net force acting on it?
20 N
1.25 N
9.8 N
10 N
Explanation - Using F = ma, F = 5 × 4 = 20 N.
Correct answer is: 20 N
Q.5 If the force acting on a body is doubled, its acceleration will:
Remain the same
Be halved
Double
Become zero
Explanation - From F = ma, acceleration is directly proportional to force.
Correct answer is: Double
Q.6 A 2 kg body moving with velocity 3 m/s comes to rest in 4 s. The retardation is:
0.75 m/s²
1.5 m/s²
3 m/s²
6 m/s²
Explanation - Retardation a = (v - u)/t = (0 - 3)/4 = -0.75 m/s².
Correct answer is: 0.75 m/s²
Q.7 The reaction force on a book resting on a table is due to:
Gravity
Table pushing up
Friction
Air resistance
Explanation - Newton's third law: the table exerts an upward force equal to the weight of the book.
Correct answer is: Table pushing up
Q.8 An object weighs 100 N on Earth. Its mass is:
10 kg
100 kg
9.8 kg
1 kg
Explanation - Weight W = mg => m = W/g = 100/9.8 ≈ 10 kg.
Correct answer is: 10 kg
Q.9 A force of 10 N is applied on a 1 kg object on a frictionless surface. The acceleration is:
10 m/s²
1 m/s²
0.1 m/s²
100 m/s²
Explanation - F = ma => a = F/m = 10/1 = 10 m/s².
Correct answer is: 10 m/s²
Q.10 Which law explains why passengers lurch forward when a car suddenly stops?
Newton's first law
Newton's second law
Newton's third law
Law of conservation of momentum
Explanation - Due to inertia, passengers tend to continue moving forward when the car stops suddenly.
Correct answer is: Newton's first law
Q.11 If mass is doubled and the force is kept constant, acceleration will:
Double
Halve
Remain same
Become zero
Explanation - F = ma => a = F/m; if m doubles, a halves.
Correct answer is: Halve
Q.12 A 10 kg block is pushed with 50 N on a frictionless surface. Its acceleration is:
0.5 m/s²
5 m/s²
50 m/s²
500 m/s²
Explanation - a = F/m = 50/10 = 5 m/s².
Correct answer is: 5 m/s²
Q.13 The force that opposes motion between two surfaces in contact is called:
Gravitational force
Tension
Friction
Normal force
Explanation - Friction always opposes relative motion between surfaces.
Correct answer is: Friction
Q.14 A 15 N force acts on a 3 kg body. What is the acceleration?
5 m/s²
0.2 m/s²
45 m/s²
1 m/s²
Explanation - a = F/m = 15/3 = 5 m/s².
Correct answer is: 5 m/s²
Q.15 Newton's second law relates:
Force and velocity
Force, mass, and acceleration
Action and reaction
Momentum and energy
Explanation - Second law states F = ma, relating force, mass, and acceleration.
Correct answer is: Force, mass, and acceleration
Q.16 A man pushes a wall with 200 N force. The wall does not move. Reaction force is:
0 N
200 N
400 N
Depends on friction
Explanation - Newton's third law: wall exerts equal and opposite force of 200 N on man.
Correct answer is: 200 N
Q.17 A car of mass 1000 kg accelerates at 2 m/s². The force applied is:
500 N
2000 N
1000 N
4000 N
Explanation - F = ma = 1000 × 2 = 2000 N.
Correct answer is: 2000 N
Q.18 When a ball is thrown vertically upwards, at the top of its path, acceleration is:
0 m/s²
9.8 m/s² downward
9.8 m/s² upward
Cannot be determined
Explanation - Gravity acts downward even at the top; acceleration = g downward.
Correct answer is: 9.8 m/s² downward
Q.19 Inertia of an object depends on its:
Force
Mass
Velocity
Acceleration
Explanation - Inertia is the property of an object to resist change in motion, proportional to mass.
Correct answer is: Mass
Q.20 Which of these forces is not a contact force?
Friction
Tension
Gravitational
Normal force
Explanation - Gravitational force acts at a distance, not by contact.
Correct answer is: Gravitational
Q.21 A 50 N force acts on a 10 kg body. Its acceleration is:
0.5 m/s²
5 m/s²
50 m/s²
500 m/s²
Explanation - a = F/m = 50/10 = 5 m/s².
Correct answer is: 5 m/s²
Q.22 A body will remain at rest unless:
Friction acts on it
Net external force acts on it
Velocity increases
Acceleration becomes zero
Explanation - Newton's first law: a body remains at rest or uniform motion unless acted upon by a net external force.
Correct answer is: Net external force acts on it
Q.23 If an object is moving in a circle at constant speed, it is:
Not accelerating
Accelerating toward center
Accelerating tangentially
At rest
Explanation - Centripetal acceleration toward the center exists even at constant speed.
Correct answer is: Accelerating toward center
Q.24 A person weighing 600 N stands on a floor. The floor exerts a normal force of:
0 N
600 N
300 N
1200 N
Explanation - According to Newton's third law, the floor pushes up with a force equal to the weight.
Correct answer is: 600 N
Q.25 A force applied on a body is in the direction of motion. The work done is:
Zero
Negative
Positive
Cannot be determined
Explanation - Work done = Force × displacement × cosθ; θ = 0° → cosθ = 1 → positive work.
Correct answer is: Positive