A student runs 10.0 km east along the course, then turns around and runs 10.0 km west along the same path. The student returns to the starting point in 50 min.
a) What is the student's average speed?
b) The student's average velocity?

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?

In a good thermo flask the main cause of heat loss is

The mantle is made up of which structural zones?