A shotgun grain weighing 20g is shot into a wooden board 10cm thick. The speed of the grain at the entrance to the wood is 400m/s and the exit 150m/s. Determine the change in grain kinetic energy​

Current from a charged capacitor lights a bulb. as time goes on the brightness of the

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?

How do you count the total number of atoms present on one side of a chemical equation?