Which is a derived unit?

An artificial satellite circles the earth in a circular orbit at a location where the acceleration due to gravity is 6.03 m/s^2. determine the orbital period of the satellite.

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.

Abox that has self-contained cable clamps holds two light switches. a two-wire no. 12 cable with ground feeds the box, and a pair of two-wire no. 12 cables (four conductors) with ground wires leaves the box to feed the light fixtures. the second switch is fed by a no. 12 jumper wire from the first switch. which one of the following box combinations would furnish the minimum allowable volume? a. two 3-inch × 2-inch × 21⁄2-inch gangable device boxes b. two 3-inch × 2-inch × 11⁄2-inch gangable device boxes c. two 3-inch × 2-inch × 23⁄4-inch gangable device boxes d. two 3-inch × 2-inch × 21⁄4-inch gangable device boxes