Which type of modulation is used by remote-control toys?

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.

The ability to make things happen is also called a. heat b. force c. matter d. energy

Suppose that a cylindrical tank 6 meters high with a radius of 2 meters is filled to the rim with water. the tank is buried so that the top of the tank is 1 meter below ground level. the space above the tank is not filled with water. calculate how much work needs to be done by a pump to pump the water out of the tank up to ground level. (the water weighs 9,800 newtons per cubic meter.)