What is the force of a 12 kg rock falling at 9.8m/s/s

Astone is dropped from a cliff and falls 9.44 meters. what is the speed of the stone when it reaches the ground? a. 13.6 m/sec b. 1.39 m/sec c. 185 m/sec d. 9.80 m/sec

Calculate a pendulums frequency of oscillation (in hz) if the pendulum completes one cycle in 0.5s.

You notice the birds sitting on the electrical wires which of the following explain why the birds don't get shocked