A) The formula for kinetic energy is E = 1/2 mv^2, so the energy of the ball is 1/2 * 2 * 10^2 = 100J.
b) Energy is always conserved, and so if no energy is lost to resistive forces then all 100J of kinetic energy came from its potential energy at the top of the track.
c) The formula for potential energy is E = mgh, which we can rearrange for h = E/mg. We know the energy, the mass and the strength of gravity, so we can find h = 100 / (2*9.81) = 5.10m.
Answer:
0.3 N
Explanation:
Electromagnetic force is F= Kq1q2/r^2, where r is the distance between charges. If r is doubled then the force will be 1/4F which is 0.3 N.
