Why is the efficiency of a machine never 100%

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. It strikes a red glider that has mass 0.600 kg and that is initially at rest.

A 6861 kg car traveling at 48 m/s is at the foot of a hill that rises 142 m in 2.3 km. At the top of the hill, the speed of the car is 10 m/s. The acceleration of gravity is 9.81 m/s 2.

A distance-time graph indicates than an object moves 100 m in 4 s and then remains at rest for 6 s. What is the average speed of the object?

Will an object with a density of 1.05 g/ml sink or float in water

What is the formula for amplitude?

You are in the lab and are given two rods set up so that the top rod is directly above the bottom one. The two straight rods 50-cm long are separated by a distance of 1.5-mm each with 15 A of current passing through them.

What is the explanation for feather beds being warm

A student wearing frictionless in-line skates on a horizontal surface is pushed by a friend with a constant force of 47 N. How far must the student be pushed, starting from rest, so that her final kinetic energy is 354 J?

Suppose a rocket ship in deep space moves with constant acceleration equal to 9.8 m/s2, which gives the illusion of normal gravity during the flight.

A canoeist on a lake throws a 0.145 kg baseball at 20.0 m/s to a friend in a different canoe. Each canoe with its contents has a mass of 120 kg, and is at rest initially.