What is the potential energy of a 0.5 kg object sitting on a shelf that is 1.5 meters high?

What object a collides with object b and bounces back its final momentum is?

Point charges q1 = 51 µc and q2 = −27 µc are placed 1.0 m apart, with q2 on the right. what is the force (in n) on a third charge q3 = 19 µc placed midway between q1 and q2? (assume the positive direction is to the right. indicate the direction with the sign of your answer.)

Which of the following are appropriate acceleration units?