Momentum and Impulse: Worksheet 5

Name

Date Pd

Momentum and Impulse: Worksheet 5

A 0.25 kg ball approaches a player at +6.2 m/s. The player kicks the ball and gives it a velocity of -12 m/s. If the player's foot is in contact with the ball for 0.021 s, compute the average force exerted on the ball. (F = -21.6N)
A force of 1500 N is required to stop a car moving at an initial speed of 26 m/s in 21 s. Compute the mass of the car. (m=1211.5 kg)
A 15,000 kg train car is rolling at a speed of 3.2 m/s. Compute the time required for a force of 1200 N to stop the car. (t=40s)
A car moving at 11 m/s crashes into an obstacle and stops in 0.26 s. Compute the force that a seatbelt exerts on a 21 kg child to bring him/her to a stop.
Ball A with a mass of 5.0 kg, moves at a velocity of 0.20 m/s. It collides with ball B, mass 10.0 kg moving in the same direction at 0.10 m/s. If the velocity of ball A is 0.08 m/s after the collision, compute the final velocity of ball B.
A 2800 kg SUV moving at some speed hits the rear end of a 950 kg car at rest. After the collision, they remain entangled and move off at 9.1 m/s. Compute the initial speed of the SUV. (v=12.2 m/s)
A 15 g bullet is fired into a 5.10 kg block at rest. After impact, the bullet and block move off at 1.0 m/s. Compute the initial speed of the bullet. (v = 341 m/s)
A car with a mass of 1350 kg, moving at a speed of 31 m/s, strikes a stationary 2170 kg car. If the cars remain together after the crash, compute the speed of the wreck.
A 6.0 g bullet moving at +120 m/s hits a stationary 5.20 kg block and ricochets in the opposite direction with speed of -110 m/s. Compute the speed of the block after the impact. (v=0.27 m/s)

10. Two objects slide over a frictionless horizontal surface. The first object, mass = 5 kg , is propelled with speed V1i = 4.5 m/s towards the second object with mass = 2.5 kg, which is initially at rest. After the collision, both objects have velocities which are directed on either side of the original line of motion of the first object. What are the final speeds of the two objects? Is the collision elastic or inelastic? (vf1= 0.46m/s and vf2 = 5.19m/s)

At an intersection a 2500 kg car travelling east at 35 m/s collides with a 500kg van traveling north at 25 m/s. Find the direction and magnitude of the velocity of the wreckage immediately after the collision, assuming that the vehicles undergo a perfectly inelastic collision( you know it means they stick together). (vf= 4.2 m/s 81.9º east of north)

A compact car, mass 900 kg moving south at 15 m/s is struck by a full-sized car mass 1500 kg, moving east at 10 m/s. The collision is perfectly Inelastic.

Sketch the situation assigning coordinate axes and identifying “ before” and “after”.

Find the direction and speed of the wreck immediately after the collision? (vi=11.27 m/s 83º east of south)

c. Extra though process: Put your “Thinking cells to work”

What if the wreck skids along the ground and comes to a stop. The coefficient of kinetic friction while the wreck is skidding is 0.55. Assume that the acceleration is constant. How far does the wreck skid? (11.55m = x)

Your buddy has been in a car accident and wants your help. She is driving her 1265 kg Car north on Rama Street when she was hit by a 925 kg compact car going west on Bulu street. The cars stuck together and slid 23.1 m at 42 degree north of west. The speed limit on both streets is 50 mph( 22m/s). Your Buddy claims that she wasn’t speeding but the other car was.

Can you prove in court that is right? Assume momentum is conserved and acceleration was constant during the skid. The coefficient of kinetic friction between tires and the pavement is 0.65.