Collisions & Motion (Momentum & Energy) Practice Problems

During a warm-up in a velodrome, Charles, an inattentive cyclist moving at a velocity of 12 m/s Î collides with Albert, moving at a velocity of -10 m/s Î. Charles and Albert and their bikes become entangled and begin to slide together on the horizontal floor. The friction coefficient between the cyclists-bikes system and the velodrome is 0.15. Find the direction of motion after the collision and the distance traveled on the floor until they stop. The combined mass of Charles and his bike is 72 kg and for Albert and his bike is 70 kg.

During a physics class field trip to a snowy hill, a sled slides down a frictionless slope and elastically strikes a stationary snowball at the bottom that is only half its mass. The slope ends 45 cm above the snow-covered plain. If the hill's height from where the sled starts is 90 cm, determine where the sled and the snowball land on the plain, considering that both leave the slope moving horizontally.

Scientists have calculated that for a particular distant massive solid planet, every couple of million years, a 1.0-km-diameter planetoid crashes into it. One such planetoid having a density of 4300 kg per cubic meter, is moving toward the planet at a speed of 25 km/s. Assuming the planetoid to be spherical, evaluate the destructive energy that will be released after it collides with the planet.

A 4.1 x 10⁵ kg satellite is heading toward another satellite in space. The former satellite's speed needs to be changed by 0.50 cm/s to avoid a collision. The thrusters onboard can exert a constant force of 3.2 N. Calculate the time for which this force must act on the former satellite to change its course sufficiently.

Calculate the average force exerted on the ball by the racket during contact when a 0.146-kg tennis ball, served horizontally at 33.0 m/s, hits the racket and is lobbed straight up to a height of 31.6 m, with the contact duration between the racket and the ball assumed to be 2.6 ms.

A catapult launches a stone vertically into a 1.41-kg piece of fruit resting on a thin horizontal surface. If the stone has a mass of 25.0 g and travels at a speed of 231 m/s, determine how high the piece of fruit will rise into the air after the stone becomes embedded in it.

The impact resistance of new motorcycle helmets is tested by striking them against rigid barriers at a speed of 20 m/s. A prototype helmet, weighing 2 kg, comes to a complete stop in 0.2 seconds upon impact. Determine the average force exerted on the helmet by the barrier during the collision.

In crash tests for new electric scooter models, scooters are subjected to controlled collisions with solid barriers at a velocity of 10 m/s. A prototype scooter, with a mass of 80 kg, takes 0.4 seconds from impact until it comes to a complete stop. Determine the average deceleration experienced by the scooter in terms of "g's".

Two pendulums are set up side by side, and each of them has a different mass. Pendulum A has a mass of 60 g, and Pendulum B has a mass of 80 g. Both pendulums are suspended from the ceiling with strings that are each 40 cm long. Pendulum A is pulled away to form a 45° angle with the vertical and then is released. What is the speed of Pendulum A just before it impacts Pendulum B?

A hockey puck weighing 170 g is hit so hard that it embeds itself into a stationary wooden log that weighs around 20 kg, making it slide for about 0.75 m on a ice surface made from wet snow. What is the initial speed of this hockey puck?