As the ball rolls down the ramp, there are changes in kinetic and potential energy. How much kinetic energy does the ball have when it reaches point B?

A) 0J
B) 25J
C) 50J
D)100J

What is the measurement of how fast an object moves relative to a reference point?

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.)

Where do magnetic lines of force enter earth?