A pendulum swings past it's pole 20 times in 18 seconds, what is the period of the pendulum?

What is relative velocity? in which condition is relative velocity known by adding the velocity of the first body and that of the second body

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?

How much work would it take to move a coulomb charge across a 4 volt potential difference?