Momentum & Impulse (DP IB Physics: HL)

A force acts on a mass of 5.0 kg and it is initially at rest.

What is the time taken for the mass to reach an acceleration of 2 m s^-2?

A body of mass 3M at rest explodes into two pieces of mass 2M and M. 

What is the ratio  and ?

A.		-1
B.	1	-1
C.		2
D.		-2

Which of the following is an elastic collision?

A ball of mass m travels horizontally and strikes a vertical wall with a speed of v_initial ms^-1. It then rebounds horizontally at speed v_final ms^-1. The ball is in contact with the wall for time Δt.

What is v_final if the ball rebounds after an impulse of magnitude I?

A stone of mass 0.5 kg is thrown with an initial speed of 10 m s^-1 at an angle θ to the vertical. P is the highest point of the motion and air resistance is negligible.

What is the momentum of the stone at P?

A truck T moving horizontally collides with an identical truck S that is at rest.

 T strikes S with speed 2v.

What is a possible outcome of the collision?

A ball of mass m strikes a vertical wall with a speed v at an angle of θ to the wall. The ball rebounds at the same speed and angle in time t. What is the magnitude of the impulse on the wall?

A ball of mass 4.0 kg, initially at rest, is acted on by a force F which varies with t.

What is the velocity of the ball after 14 s?

Which of the following is true for momentum and impulse?

Two balls m and 2m collide elastically with speeds v and 2v respectively. After the collision, they both move in opposite directions.

What speed does the 2m ball move with after the collision?

Water is ejected from the nozzle of a hose through a hole of a diameter 2 cm. The water leaves the nozzle of the hose with a velocity of 25 cm s^–1 and travels horizontally towards a wall, as shown below.

After colliding with the wall the water has zero velocity.  Water has a density of 1 g cm^–3.

What is the force exerted by the water on the wall?

A ball of mass 0.60 kg is kicked off a cliff with a horizontal velocity of 3.0 m s^–1.  It follows the path of a projectile shown below and lands with a velocity of 4.0 m s^–1 at an angle of 30^o to the ground.  Air resistance is negligible during the flight.

What is the magnitude of the change in momentum of the ball between the top of the cliff and the ground below?

You may need to use the following trigonometric values to help you:

cos(30) = 

sin(30) = 

A BB gun fires 4 g ball bearings at a rate of 100 balls per minute. The balls leave the BB gun at a velocity of 20 m s^–1 and strike a fixed steel block.  The balls rebound off the block with the same velocity as they were fired.

What is the average force exerted on the steel container?

Two trolleys, X and Y, are connected by an elastic cord, of negligible mass, as shown below. Trolley X is twice the mass of trolley Y.

The two trolleys are pulled apart so that the elastic cord is stretched. The trolleys are then released at the same time and move towards each other.  The trolleys stick together on impact. 

Just before the trolleys collide, the speed of trolley X is 20 cm s^–1.

What is the speed of the trolleys after they collide?

The diagram below shows a block of mass 2 kg sliding down a rough slope from rest against a constant friction force of 2.5 N.

Use the following assumptions to help you:

Acceleration due to free fall is 10 m s⁻²

cos(20) = 0.9

sin(20) = 0.3

What is the momentum of the block along the slope after 5 seconds?

A car of mass 3000 kg is travelling at 5 m s^–1 when it collides with a wall and is brought to rest.  The force-time graph of the impact is shown below.

What is the maximum force exerted on the car?

The variation of the force, F, with time, t, acting on a mass of 160 g is shown on the graph below.

The velocity of the body at t = 10 ms is 5 m s^–1.

What is the velocity of the body at t = 35 ms?

Particle P has a mass m and is moving towards a stationary particle, Q, of mass M.  P is travelling with a velocity of u before colliding head on with particle Q.  The collision between the particles is elastic.

What is the velocity of particle Q after the collision? 

Two spheres approach each other along the same straight line. Their speeds are u₁ and u₂ before collision, and v₁ and v₂ after collision, in the directions shown below

Which equation is correct if the collision is perfectly elastic?