# Completely Inelastic Collisions Practice Problems

Computer games can simulate an encounter between predator and prey. The prey will retaliate to protect its young ones while the predator attacks. In one simulation, a 1.10 kg duck is chasing a 2.80 kg eagle. The duck, flying at 8.90 m/s, hits the eagle perpendicularly and bounces back at 4.80 m/s. If the eagle was flying at 14.8 m/s before the collision, what is the change in its direction of motion (in degrees)?

Jay with a mass of 60.0 kg skates at 10.0 m/s due north on a frozen horizontal surface towards a crossroad. Kay of mass 51.0 kg who is crossing through the crossroad gets shocked and stops upon spotting Jay. Jay collides with Kay. Jay travels at 6.2 m/s directed at 28.0° east of north after the collision. Determine the magnitude and direction of Kay's velocity following the collision. You may ignore friction.

Science students decide to perform an experiment on a horizontal and frictionless rink. John (mass = 70.0 kg) stands still while James (mass = 53.0 kg) skates in a straight line and collides with John with a velocity of 12.5 m/s. After the collision, James is deflected at 46.8° from his original direction and has a speed of 6.50 m/s. Determine the change in kinetic energy of the system following the collision.

A team of researchers is studying collisions on a (frictionless) frozen pond. Two volunteers, Joy and Glad perform the demonstration. Joy of mass 62.0 kg stands still. Glad of mass 52.0 kg slides towards Joy at a velocity of 11.5 m/s to perform a collision. After the collision, Glad is moving at 7.00 m/s directed at 42.4° from her initial direction. Determine the magnitude and direction of Joy's velocity following the collision.

Bumper technology in vehicles is designed to absorb and store kinetic energy in case of a collision, then release it to the vehicles as they separate. The efficiency of the technology decreases as collision speed increases. During a design analysis by a manufacturer, a car of mass 900 kg is headed east at 1.40 m/s when it collides with a car of mass 650 kg headed west at 1.20 m/s. Analysis of the after-collision period shows that the 900 kg Car is moving at 0.180 m/s in its original direction. What is the change in the overall kinetic energy of the two cars for the collision? Ignore friction.

Bumpers in cars absorb energy in low-speed collisions and release the energy again causing cars to bounce off. An accident occurs when an 850 kg car moving to the east at 1.30 m/s collides with a second car of mass 400 kg headed to the west at 1.00 m/s. The velocity of the 850 kg car after the collision is determined to be 0.435 m/s in its earlier direction. Determine the speed of the 400 kg car after the collision.

Two blocks are placed on a horizontal frictionless bench. Block A of mass 3.50 kg is fired toward block B (mass 2.50 kg) which is kept at rest. After the collision, Block A moves to the right with a speed of 1.29 m/s while block B moves to the right with a speed of 1.96 m/s. What is the change in total kinetic energy of the system due to the collision?

During your leisure time, you conduct an experiment on the collision of blocks. You set a system that fires blocks toward each other. In one setup, you keep block A of mass 0.850 kg at rest and fire block B of mass 0.650 kg towards block A. After the collision, you measure the velocities of the blocks to be 1.76 m/s to the left for block A and 0.202 m/s to the right for block B. Determine the speed of block B before the collision.

You are standing on a wet surface shortly after it rains. The ground is highly slippery, therefore frictionless. Your colleague throws a 550 g ball toward you at a horizontal speed of 7.60 m/s. You deflect the ball backwards so that it moves towards your colleague at 11.3 m/s. If your mass is 65.8 kg, what's your speed after the collision?

Kids find it fun playing on frozen (frictionless) lakes. A 16.8 kg kid is sliding at 3.60 m/s left towards a playing partner of mass 14.5 kg who is sliding to the right at 3.20 m/s. They hold onto each other when they meet during the collision. Determine the loss in mechanical energy during the interaction.

An algae-covered horizontal section of a footpath is wet and highly slippery, and hence frictionless. Kids find it enjoyable to jog and slide toward each other on this surface. An 18.2 kg kid is sliding at 4.30 m/s east while another of mass 16.3 kg is sliding at 3.80 m/s to the west. The kids collide and hold onto each other. Determine the velocity magnitude and direction of the kids shortly after they have collided.

Two skaters are headed on a collision course on a smooth and frictionless frozen surface. The skaters manage the situation by grabbing each other rather than hitting each other. A 68.0 kg skater is traveling at 7.50 m/s west while the other has a mass of 72.0 kg and is traveling east at 4.20 m/s. Determine the magnitude and direction of both skaters' velocity immediately after the collision.

A player is standing on frictionless roller skates on a playing field. During a practice session, the player catches a 450 g ball that is traveling horizontally at 12.5 m/s. If the player's mass including the roller skates is 68.0 kg, what is the speed of the ball and the player after the catch?