Class 9 Physics Chapter 9 Force and Law of Motion MCQs

Class 9 Physics MCQs for Chapter 9 are available here online for students, along with their answers. MCQs with answers for Class 9 Physics are prepared as per the latest exam pattern. These multiple-choice questions are prepared as per the latest CBSE syllabus and NCERT guidelines. Solving these objective questions will help students build their problem-solving skills and score good marks in the board exams.

Download Chapter 9 Force and Law of Motion MCQs PDF by clicking on the button below.
Download PDF

Class 9 Force and Law of Motion MCQs

Check the multiple-choice questions for the 9th Class Physics Law of Motion Chapter. Each MCQ will have four options here, out of which only one is correct. Students have to pick the correct option and check the answer provided here.

1. Which of the following is NOT true for an object moving along a straight path in an accelerated motion?

1. Its velocity always changes
2. Its speed keeps changing
3. (d) It always goes away from the Earth
4. It always goes away from the Earth

Answer: c. A force is always acting on it

Explanation: For the accelerated motion of an object along a straight line, a non-zero force must be acting on the object, which is increasing its velocity and speed. However, the direction of force is not given so it can’t be determined whether it is moving away from earth or not.

2. The inertia of an object causes the object to

1. decrease its speed
2. Increase its speed
3. resist any change in the state of its motion
4. decelerate due to friction

Answer: (c) resist any change in the state of its motion

Explanation: The inertia of an object causes the object to resist any change in the state of its motion.

3. Which of the following is true for the third law of motion?

1. Action-Reaction pair always acts on the same body.
2. They act on different bodies in opposite directions
3. Action-Reaction pairs have the same magnitudes and directions
4. Act on either body at normal to each other

Answer: (b) They act on different bodies in opposite directions.

Explanation: Action-Reaction always acts on different bodies in opposite direction and are equal in magnitude.

4. Which of the following is the SI units of force?

1. Kgm/s²
2. Kgm/^-s
3. Newton-metre
4. Newton

Answer: (d) Newton

Explanation: Newton is the SI unit of force.

5. If the mass of the body is doubled and its velocity becomes half, then the linear momentum of the body will

1. become double
2. remain the same
3. become half
4. become four times

Answer: (b) remain the same

Explanation: If the body’s mass is doubled and its velocity becomes half, then the body’s linear momentum will remain the same.

6. The linear momentum of an object is 250 g cm/s. If the velocity of the object is 5 m/s, then the mass of the object is

1. 0.5 g
2. 5 kg
3. 0.5 mg
4. 5 mg

Answer: (a) 0.5 g

Explanation: Given, velocity, v = 5 m/s = 500 cm/s, momentum, p = 250 g cm/s, mass, m =?
We know that, momentum of a body is given by p = mv
or, m = p/v = 250/500 = 0.5 g

7. Which of the following is true about force?

1. Force is invisible
2. Force can move a body
3. It can deform a body
4. All of the above

Answer: (d) all of the above

Explanation: All of the given points are true for force.

8. A goalkeeper in a football game pulls his hands backwards after holding the ball shot at the goal. This enables the goalkeeper to

1. increase the rate of change of momentum
2. decrease the rate of change of momentum
3. increase the force exerted by the balls on the hands
4. exert larger force on the ball

Answer: (b) decrease the rate of change of momentum

Explanation: A goalkeeper in a football game pulls his hands backwards after holding the ball shot at the goal, enabling the goalkeeper to decrease the rate of change of momentum.

9.Which law is also known as the law of inertia?

1. Newton’s first law of motion
2. Newton’s second law of motion
3. Newton’s third law of motion
4. Law of conservation of momentum

Answer: (a) Newton’s first law of motion

Explanation: The inertia of a body is the tendency to not change its static or motional state. Newton’s first law of motion says that a static body will remain motionless, and a body in motion will stay in motion until a force acts on it. Therefore, Newton’s first law is associated with inertia and is also known as the law of inertia.

10. A passenger in a moving train tosses a coin that falls behind him. It means that the motion of the train is

1. uniform
2. accelerated
3. retarded
4. along circular tracks

Answer: (b) accelerated

Explanation: A passenger in a moving train tosses a coin that falls behind him. It means that the motion of the train is accelerated.

Stay tuned to BYJU’S and Fall in Love with Learning!