A4.50-volt personal stereo uses 1950 joules of electrical energy in one hour. what is the electrical resistance of the personal stereo?

The stereo uses an energy of  in a time , therefore the power of the stereo is given by


We also know that the power of an electrical device is related to its voltage, V, and its resistance, R, by the following equation

therefore, we can rearrange the equation to calculate the resistance of the stereo:

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.