Conservation of Momentum

Q.

State and explain the law of conservation of linear momentum.

Q.

How do you calculate the change in momentum of an object?

Q.

A cricket ball of mass 100g has an initial velocity $u=(3i+4j)m/s$and a final velocity $v=-\left(3i+4j\right)m/s$ after being hit.

Find the change in momentum.

1. $0$

2. $-\left(0.45i+0.6j\right)$

3. $-(0.9i+1.2j)$

4. $-5\left(i+j\right)$

Q.

The total momentum of a gun-bullet system remains unchanged after the shot is fired(Assume that no external force is acting on the system).

1. True
2. False

Q.

What do we get by the product of mass and velocity?

Q.

When a cracker at rest explodes into two equal parts, in which of the following ways will these parts move?

1. Opposite directions with equal velocities.

2. Opposite directions with unequal velocities.

3. Opposite directions with equal or unequal velocities.

4. Same direction with equal velocities.

Q.

What is the impact called that a body can produce due to the combined effect of mass and velocity ? Name it's unit. [2 MARKS]

Q. A car weighing $1000kg$ collides with a stationary $50kg$ trolley, and imparts a velocity of $75m{s}^{-1}$ to it. Find the speed with which the car was moving (Assume that the car comes to a stop after the collision and neglect friction at the time of collision).

1. $3.25m{s}^{-1}$
2. $3.5m{s}^{-1}$
3. $4.25m{s}^{-1}$
4. $4.75m{s}^{-1}$

Q.

Give two examples where condition of linear momentum can be applied.

Q.

Conservation of linear momentum for a system is applicable only when the external forces acting on a system are zero.

1. True
2. False

Q. A bullet is fired at a speed of $300m{s}^{-1}$ from a gun of mass $2kg$. If the gun recoils with a speed of $2.4m{s}^{-1}$, find the mass of the bullet.

1. $16g$
2. $20g$
3. $24g$
4. $28g$

Q.

State and verify law of conservation of momentum.

Q.

A bullet of mass $7g$ is fired into a block weighing $7kg$ which is free to move. Calculate the initial velocity of a bullet if the velocity of the block with the bullet inside is $0.7m/s.$

Q.

From a rifle of mass $4kg$, a bullet of mass $50g$ is fired with a velocity of $35{ms}^{-1}$​ with respect to the ground. Calculate the recoil velocity of the rifle.

1. $0.4375{ms}^{-1}$​

2. $1{ms}^{-1}$​

3. $2.5{ms}^{-1}$​

4. $0{ms}^{-1}$​

Q.

A cannon of mass 1000 kg can fire a bolt of 20 kg with a muzzle velocity of 300 m/s. If the cannon is free to move, the backward velocity of cannon after the bolt is fired is:

1. 10 g mass

2. 25 g mass

3. 20 g mass

4. 15 g mass

Q. Write a note on propulsion system of rocket

Q. Momentum?

Q. The canon experiences a recoil after firing in order to conserve:

1. velocity
2. momentum
3. speed
4. mass

Q. A cannon ball of mass $2kg$ is fired at a target $500m$ away. The $400kg$ cannon recoils with a velocity of $2m{s}^{-1}$. Assuming cannon ball moves with constant velocity, when does it hit the target?

1. 5 sec

2. 10 sec

3. 15 sec

4. 2 sec

Q. THE WEIGHT OF THE OBJECT IS ZERO AT?

Q.

A wooden block of mass $1kg$ travelling in a straight line with a velocity of $10m{s}^{-1}$ collides with and sticks to a stationary concrete block of mass $5kg$. After the collision they move together in the same straight line. Find the velocity of the combined object.

1. $1.67m{s}^{-1}$

2. $2m{s}^{-1}$

3. $2.34m{s}^{-1}$

4. $2.67m{s}^{-1}$

Q. Which among the following is an example of a contact force?​

1. 
   Magnetic Force​

2. 
   Gravitational Force​

3. 
   Frictional Force​
4. 
   Electrostatic Force​

Q. A loaded transport truck with a mass of 38000 kg is travelling at 1.20 m/s. What will be the velocity of a 1400 kg car if it has the same momentum?

1. 30 m/s
2. 15 m/s
3. 32.57 m/s
4. 32.67 m/s

Q. Two objects of masses 100 g and 200 g are moving along the same line and direction, with velocities $2m{s}^{-1}$ and $1m{s}^{-1}$, respectively. They collide and after the collision, the second object moves with a velocity of $1.67m{s}^{-1}$. Determine the velocity of the first object:

1. $0.66m{s}^{-1}$
2. $0.55m{s}^{-1}$
3. $0.66m{s}^{-2}$
4. $1.66m{s}^{-1}$

Q. Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each object is $2.5m{s}^{-1}$ before the collision during which they stick together. What will be the velocity of the combined object after collision?

1. 3.75 m/s
2. 3 m/s
3. 0.75 m/s
4. 0 m/s

Q. A bullet weighing $30g$ is fired at a speed of $120m{s}^{-1}$. If the gun recoils with a speed of $4m{s}^{-1}$, find the mass of the gun.

1. $360g$
2. $480g$
3. $640g$
4. $900g$

Q. Write a note on propulsion system of rocket

Q. A sofa, ABCD, is placed on a slippery surface. Two forces of 5 N are applied on AD and CD. Tap on the direction in which the sofa will move.

1. 
2. 
3. 

Q.

Two unequal masses possess the same K.E. Then, the heavier mass has

1. greater momentum

2. smaller momentum

3. the same momentum as the lighter mass

4. greater speed

Q. If the $KE$ of a particle becomes four times its initial value, then the new momentum is more than its initial momentum by

1. $50$ %
2. $100$ %
3. $125$ %
4. $150$ %