Why can't perpetual motion not work on earth?

An oscillator makes four vibrations in one second. What is its period and frequency?

The higher the amplitude of the wave, the greater its intensity and the greater its loudness. true or false?

Correctly round the following number to the whole number 2.35784

The "atomic weight" of an atom reflects the average number of A) protons. B) neutrons. C) electrons. D) protons + neutrons. E) protons + neutrons + electrons.

The outer planets are known as the

If you lived downhill from a volcano and lava started to flow toward your home what could happen?

A battleship simultaneously fires two shells toward two identical enemy ships. One shell hits ship A, which is close by, and the other hits ship B, which is farther away. The two shells are fired at the same speed.

A horse canters away from its trainer in a straight line, moving 37 m away in 9.1 s. It then turns abruptly and gallops halfway back in 1.8 s. Calculate its average speed for the entire trip. Express your answer using two significant figures.

An early submersible craft for deep-sea exploration was raised and lowered by a cable from a ship. When the craft was stationary, the tension in the cable was 7000 N {/rm N}.

What are the components of earths life support system