A0.75-kg ball falls vertically downward from a height of 55.0 m and rebounds upward. if the ball reaches a height of 30.0 m and the contact between the ball and ground lasts 2.50 ms, what is the average force exerted on the ball by the ground?

Why don't you see your reflection in water with waves or repples

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?

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.)