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Class 11  ยป  Physics  ยป  Laws of Motion

Linear Momentum - UNSOLVED PRACTICE SET

Class 11

Chapter: Laws of Motion | Topic: Linear Momentum

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Study Material.
Class 11

LINEAR MOMENTUM - UNSOLVED PRACTICE SET

Topic: Linear Momentum

Time: 40 mins | Marks: 30 | Difficulty: Medium

Multiple Choice Questions

Q1. Linear momentum of a body is defined as:

  1. Mass ร— acceleration
  2. Mass ร— velocity
  3. Force ร— time
  4. Mass ร— displacement

Q2. The SI unit of linear momentum is:

  1. kg m/sยฒ
  2. kg m/s
  3. N s
  4. Both (b) and (c)

Q3. A body of mass 2 kg moving with velocity 3 m/s has a momentum of:

  1. 6 kg m/s
  2. 1.5 kg m/s
  3. 5 kg m/s
  4. 9 kg m/s

Q4. If the momentum of a body is doubled by keeping its mass constant, its kinetic energy becomes:

  1. Double
  2. Four times
  3. Half
  4. Unchanged

Q5. Two bodies of masses m and 2m have the same momentum. The ratio of their kinetic energies is:

  1. 1 : 1
  2. 1 : 2
  3. 2 : 1
  4. 4 : 1

Q6. The direction of linear momentum of a body is:

  1. Same as the direction of velocity
  2. Opposite to the direction of velocity
  3. Perpendicular to the direction of velocity
  4. Independent of the direction of velocity

Short Answer Questions

Q7. Define linear momentum. Is it a scalar or vector quantity? Explain.

Q8. Derive the relationship between kinetic energy and linear momentum.

Q9. A bullet of mass 10 g is fired with a velocity of 500 m/s from a rifle of mass 4 kg. Calculate the recoil velocity of the rifle.

Q10. In a cricket match, a bowler throws a ball of mass 160 g at 144 km/h. A batsman hits it back at 108 km/h. Calculate the change in momentum of the ball.

Q11. Two bodies A and B have masses in the ratio 1:2 and velocities in the ratio 2:1. Compare their momenta and kinetic energies.

Q12. Why is it easier to catch a cricket ball by moving your hands backward than by keeping them stationary? Explain using the concept of momentum.

Long Answer Questions

Q13. Define linear momentum and derive its relationship with Newton's second law of motion. Show that F = dp/dt is a more general form of Newton's second law than F = ma. Discuss situations where F = dp/dt is more appropriate.

Q14. A ball of mass m moving with velocity u collides head-on with a wall and rebounds with the same speed.

(a) Calculate the change in momentum of the ball.

(b) If the collision lasts for time ฮ”t, calculate the average force exerted by the wall on the ball.

(c) Using Newton's third law, calculate the force exerted by the ball on the wall.

(d) Explain why the wall does not move despite experiencing this force.

Q15. A rocket of mass 5000 kg is launched vertically upward. It ejects gases at a rate of 50 kg/s with an exhaust velocity of 800 m/s relative to the rocket.

(a) Calculate the thrust force on the rocket.

(b) If the rocket is to lift off, what is the minimum thrust required? (Take g = 10 m/sยฒ)

(c) Calculate the initial acceleration of the rocket at lift-off.

(d) Explain how the principle of conservation of momentum applies to rocket propulsion.

Application-Based Problems

Q16. A 2000 kg car moving at 20 m/s collides with a stationary truck of mass 8000 kg. After the collision, the car and truck move together.

(a) Calculate the total initial momentum of the system.

(b) Calculate their common velocity after the collision.

(c) Calculate the kinetic energy before and after the collision.

(d) Is kinetic energy conserved in this collision? What type of collision is this?

Q17. A machine gun fires 600 bullets per minute. Each bullet has a mass of 20 g and a muzzle velocity of 400 m/s.

(a) Calculate the momentum of each bullet as it leaves the gun.

(b) Calculate the total momentum imparted to the bullets in one minute.

(c) Calculate the average recoil force on the gun.

(d) If the gun is mounted on a platform of mass 50 kg, calculate the recoil velocity of the platform per second.

Q18. In a physics lab, two students conduct an experiment with two trolleys on a frictionless track. Trolley A (mass 2 kg) moves at 3 m/s and collides with stationary Trolley B (mass 3 kg). They stick together after collision.

(a) Calculate the initial momentum of the system.

(b) Calculate their common velocity after collision.

(c) Calculate the loss in kinetic energy.

(d) The students repeat the experiment with Trolley B initially moving at 2 m/s towards Trolley A. Calculate the new common velocity after collision.

(e) What conclusion can you draw about the conservation of momentum from these experiments?


Total: 30 Marks | Time: 40 mins

Explore more topics in Laws of Motion

Aristotles Fallacy and Galileos Observation Newtons First Law and Inertia Newtons Second Law F equals dp by dt Newtons Third Law Conservation of Momentum Equilibrium of a Particle Common Forces Friction Tension Normal Static and Kinetic Friction Rolling Friction Circular Motion Dynamics Solving Problems Using Free Body Diagrams