A Pendulum, swinging back and forth, rises at the end of its swing to a position 15 cm higher than its lowest point. How fast is it going at the lowest point

An observer that stands still as the electron moves by him, will observe

How much energy must a refrigerator absorb from 225 g of water so that the temperature of the water will drop from 35°c to 5°c

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.