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The quantity termed momentum that defines motion in an isolated collection of objects never changes, according to the conservation of momentum principle; that is, the overall momentum of a system stays constant. Momentum is equal to the force necessary to bring an item to a complete halt in a given amount of time when its mass is multiplied by its velocity. The overall momentum of a group of objects is equal to the sum of their individual momenta. However, since momentum is a vector that includes both the direction and amplitude of motion, the momenta of objects moving in opposing directions may cancel out to produce a total sum of zero.
1. In a horizontal plane, an explosion splits a rock into three pieces. Two of them diverge at a straight angle to one another. The first component of mass 1-kilogram travels at a speed of 12 m/s, whereas the second part of mass 2 kg travels at a speed of 8 m/s. The mass of the third portion is-
(a) 3 kg
(b) 5 kg if it flies away at 4 m/s
(c) 7 kilos
(d) 12 kilos
Answer- b
Explanation- m1v1+m2v2=m1v1’+m2v2,the formula for the Law of Conservation of Momentum is used.
2. A rigid ball of mass m collides with a rigid wall at 600 mph and is reflected without losing velocity. The wall’s impulse on the ball will have the following value-
(a) mv
(b) 2mv
(c) mv/2
(d) mv/3
Answer- a
Explanation- a is answer as momentum is conserved
3. How is it possible for a jet aircraft to fly through the air?
(a) The thrust of the jet aircraft compensates for gravity
(b) The weight of the air is the weight of the plane
(c) The force of gravity does not affect on bodies travelling at high speeds
(d) The flow of air around the wings causes an upward force that compensates for gravity
Answer- a
Explanation- As it creates pressure difference by wings.
4. A player catches a 150-gram ball travelling at 20 metres per second. If the catching procedure needs to be done in 0.1 second. What is the force that the ball exerts on the player’s hands?
(a) 3000 N
(b) 300 N
(c) 30 N
(d) 0.3 N
Answer- c
5. A force acting on a ball of mass 150 g for 0.1 second creates a 20 ms-2 acceleration. What is the amount of this force?
(a) 0.5 N-s
(b) 0.1 N-s
(c) 0.3 N-s
(d) 1.2 N-s
Answer- c
6. A particle of mass m collides with a stationary particle of mass 2m and adheres to it at a velocity of v. The system’s speed will be-
(a) v/2
(b) 2v
(c) v/3
(d) 3v
Answer- c
Explanation- m1v1+m2v2=m1v1’+m2v2,the formula for the Law of Conservation of Momentum is used.
7. On what is the rocket’s motion based?
(a) Mass
(b) Linear Momentum
(c) Kinetic Energy
(d) Angular Momentum
Answer- b
Explanation- As rockets travel in straight directions for most of the time.
8. A body with constant momentum must have constant-
(a) Force
(b) Velocity
(c) Acceleration
(d) All of these
Answer- b
Explanation- As without velocity momentum would be zero.
9. Which of the following is closely connected to momentum?
(a) Force
(b) Velocity
(c) Acceleration
(d) All of these
Answer- b
Explanation- As velocity is used in momentum.
10. A projectile with a mass of 5 grams is fired from a gun with a mass of 5 kg. If the recoil velocity is 500 m/s, what is the muzzle velocity?
(a) 500 m/s
(b) 5 m/s
(c) 50 m/s
9d) 0.5 m/s
Answer- d
Explanation- m1v1+m2v2=m1v1’+m2v2,the formula for the Law of Conservation of Momentum is used.
11. Rocket engines lift rockets off the ground because high-velocity hot gas-
(a) pushes against the air
(b) pushes against the earth
(c) heats the air, which lifts the rocket
(d) reacts against the rocket and pushes it up.
Answer- d,
Explanation- Pushes the rocket up by reacting against it.
12. A 5 m rope is held on a frictionless surface with a 5 N force applied to one of its ends. What is the rope tension at 1 metre from this end?
(a) 1 N
(b) 4 N
(c) 3 N
(d) 5 N
Answer- b
13. A system’s momentum is preserved-
(a) Always
(b) Never
(c) When the system is not subjected to an external force
(d) None of the above
Answer- c
14. On smooth tracks, a 1000 kg wagon travels at 50 km/h. The wagon is then loaded with a payload of 250 kg. What is the speed at which it is moving?
(a) 20 kilometres per hour
(b) 50 kilometres per hour
(c) 40 kilometres per hour
(d) 2.5 kilometres per hour
Answer- c
Explanation- m1v1+m2v2=m1v1’+m2v2,the formula for the Law of Conservation of Momentum is used.
15. An iron ball with a mass of 100 g and a velocity of 10 m/s collides with the wall at a 300-degree angle and bounces back at the same angle. If the time it takes for the wall and the ball to make contact is 0.1 second. What is the force that the ball is subjected to?
(a) 0.1 N
(b) 1 N
(c) 10 N
(d) 100 N
Answer- c
16. If a force of 50 dynes is applied to a 5 g body that is at rest for 3 seconds, the impulse is-
(a) 0.15 x 10-3 Ns
(b) 0.98 x 10-3 Ns
(c) 1.5 x 10-3 Ns
(d) 2.5 x 10-3 Ns
Answer- c
17. Think on these two statements-
- The system’s linear momentum stays constant.
- The system’s centre of mass stays at rest.
(a) A presupposes B, and B presupposes A.
(b) A does not presuppose B, and B does not presuppose A.
(c) A presupposes B, but B does not presuppose A.
(d) B presupposes A, but A does not presuppose B.
Answer- d
18. Two bodies are propelled from the ceiling in opposite directions at the same speed. If air resistance isn’t taken into consideration, the following will happen-
(a) If the masses of the bodies are the same, they reach the ground with the same magnitude of momenta.
(b) they have the same kinetic energy when they hit the ground.
(c) they arrive on the earth at the same time.
(d) both (a) and (c) are accurate
Answer- d
19. In a stunt film, the hero shoots 50 g bullets at a speed of 1.0 km/s from a machine gun. What is the average force he exerts on the machine gun if he shoots 20 shots in four seconds?
(a) 200 N
(b) 220 N
(c) 250 N
(d) 270 N
Answer- c
