Aball is thrown straight up into the air. at each of the following instants, is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? air resistance may be neglected.
a) just after leaving your hand?
b) at the very top (maximum height)?
c) just before hitting the ground?

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

The motor m applies a time-varying force of f (200 t) n, where t is in seconds. box b with mass 200 kg starts from rest, and the coefficients of kinetic and static friction are 0.2 and us 0.3 the acceleration due to gravity is g 9.8 m/s2 b 300 a) find the time ' when the box starts to move. b) calculate the speed of the crate at 3 s c) calculate the power delivered by the motor at t 3 s

Most short-period comets do not have randomly oriented orbits because