A bus can reach a length of 30 m long with two trailers and they have a total mass of 28 × 103 kg. Imagine a safety test with one of these buses and a truck with a mass of 12 × 103 kg. The truck with an unknown speed hits a bus that is at rest so that the two vehicles travel together with a speed of 3.0 m / s. Calculate the speed of the truck before the collision.

an iron ball with a mass of 67.5 kg is traveling with an initial velocity of 20.5 m/s. the ball is hit with a hammer, which remains in contact with the ball for 0.20 sec.  how much force must the hammer hit the ball with to cause it to change directions?

A skater of mass 72.5 kg initially moves in a straight line at a speed of 4.80 m/s. The skater approaches a child of mass 35.0 kg, whom he lifts on his shoulders. Assuming there are no external horizontal forces, what is the skater's final velocity?

During a car collision, the knee, thighbone, and hip can sustain a force no greater than 4000 NN. Forces that exceed this amount could cause dislocations or fractures. Assume that in a collision a knee stops when it hits the car's dashboard. Also assume that the mass of the body parts stopped by the knee is about 20% of the total body mass. The person with a mass of 90 kgkg is initially traveling at 18 m/sm/s (40 mi/hmi/h).  What minimum stopping time interval in needed to avoid injury to the knee?  What is the minimum stopping distance?

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A 0.6 Kg football is thrown with a velocity of 22 m/s to left. A stationary receiver catches the ball and brings it to rest in 0.03 s. What is the force exerted on the ball by the receiver? Show the procedure, result with units and direction

A 76.1 kg astronaut of holding a 12.3 kg tool pack while drifting at 10.6 m/s to the right. She throws the tool pack away so that it is drifting at 1.5 m/s to the left. How fast is she moving after the throw? Assume that they are out in deep space with no other forces acting on them.

A car (VW) and a truck (C) collide inelastically (stick together). The impact is made in a very short time of t= 0.1 s. Initial speed Vvw=40.0 m/s Cv=30 m/s Masses mvw = 900.0 kg mc = 2000.0 kg Find the final velocity of the vehicles. Find the average acceleration of each vehicle Find the average force over each vehicle. Find the initial kinetic energy. Find the final kinetic energy.

A 7.500 E+3-kg truck moving east at 10.3 m/s collides with a 2.500 E+3-kg car moving west at 35.0 m/s. The collision takes place over a time interval of 0.5 s. The car and the truck stick together after the collision. Find the force (in N) of the car on the truck during the collision. Call this force positive if it points to the east, and negative if it points to the west. (Could you give an explanation on how to transfer/ convert E +3)

A 2.00 kg ball falls off a 200.00 cm high wall. If the time during the collision is 0.050 seconds, what is the force of impact caused by the ground on the ball? USE SIGNIFICANT FIGURES in the answer!