The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that .
the planets will eventually fall into the Sun
a force is acting on the planets
the planets have angular momentum
the planets are always accelerating

Energy is the ability to do work which measures what

Jackson is designing a new heater, and he wants to experiment with different thermally conductive materials. which of these materials would be useful in conducting heat?

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?