How does the current in a series circuit compare

The image shows a pendulum in simple harmonic motion the pendulum starts at a and swing to e

Which changes of state do the labels represent? a: b: c:

Abatter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. the ball remains in contact with the bat for 2.0 ms. what is the magnitude of the average force exerted by the bat on the ball?