In a bar magnet we say that like poles do what?

Aplane travels 1000 miles in 5 hours .what is the planes average speed?

The energy equivalent of the rest mass of an electron is

Which body is in equilibrium? (1) a satellite orbiting earth in a circular orbit (2) a ball falling freely toward the surface of earth (3) a car moving with a constant speed along a straight, level road (4) a projectile at the highest point in its trajectory