A 12.2 kg ball moving to the right at 5.8 m/s collides elastically with a 9.0 kg block moving at 1.6 m/s . Find the final velocity of the 9.0 kg block.

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.)