Why is a train more difficult to stop than a rolling ball, even if they are traveling at the same speed?

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?

Arocket starts from rest and moves upward from the surface of the earth. for the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 12.80 m/s32t, where the +y-direction is upward. (a) what is the height of the rocket above the surface of the earth at t = 10.0 s? b) what is the speed of the rocket when it is 325 m above the surface of the earth?

You need to fill a basketball with air to play with it. you know that your pump expels air at a velocity of 6 cm/s. you know that the volume flow rate of air being pumped into the basketball is 103 cm^3/s. what is the diameter of your needle?