Extra Calculation Questions - Newton Laws

NEWTON’S LAWS AND LINEAR MOMENTUM

1.       A tennis ball whose mass is 150 g is moving at speed of 20 m/s. It then brought to rest by another player in 0.05 s. Calculate the average force applied.

2.       A rocket of mass of 2 x 10⁴ Kg is launched by applying a force of 5 x 10⁶ N for 20 seconds. Calculate the velocity it attains at the end of the 20 seconds.

3.       A 3 Kg hammer is used to drive a nail into piece of wood. If at the time of impact, the hammer’s speed is 5 m/s and drives the nail 1 cm into the wood. Find;

i)        The acceleration

ii)       The force exerted

iii)     The time of impact

4.       A 16 Kg mass travelling to the right at 5 m/s collides with a 4 Kg mass travelling to the left at 5 m/s.

i)        What is the momentum of each mass?

ii)       What is their total momentum?

iii)     If the masses stick together when they collide, what is their final velocity?

5.       The rocket is pushing out exhaust gas at the rate of 100 Kg/s. The velocity of the gas is 200 m/s. Calculate the forward force or thrust on the rocket.

6.       A ball A of mass 100 g moving with a velocity of 5 m/s makes a ‘head – on’ collision with a ball B of mass 200 g moving with a velocity of 1 m/s in the opposite direction. If A and B stick together after the collision their common velocity v in the direction of A

7.       A trolley A of mass 2 Kg travelling at 5 m/s collides with a stationary trolley B of mass 3 Kg. After the collision the two travel on together at 2 m/s.

i)        What is the momentum of A before collision?

ii)       What is the momentum of A after collision?

iii)     Account for the change in the momentum of A

iv)     What is the kinetic energy of A before collision?

v)       What is the kinetic energy of each trolley after collision?

vi)     During the collision, the kinetic energy gained by B is less than the kinetic energy lost by A. how much kinetic energy is unaccounted for, and what has become of it?

8.       A snooker ball B makes in impact with an identical stationary ball C. Before impact B has a velocity of 2 m/s and it follows along the same path with a velocity of 0.2 m/s; calculate the velocity of C after impact.

9.       A trolley of mass 2 Kg is moving on a horizontal surface at a velocity of 2 m/s. Another trolley of mass 1 Kg moving at 6 m/s in the same direction hits the first trolley from behind. The two then moves together in the same direction. Determine the final velocity of both trolleys.

10.   A steel ball of mass 80 g is released from rest at a height of 1.25 m above a rigid horizontal metal plate. After the rebound, the ball rises vertically to a height of 1.00 m above the plane. Calculate the;

i)        Velocity of the ball just before the impact.

ii)       Momentum of the ball just before the impact.

iii)     Momentum of the ball just after the impact.