Select all the correct answers. A free-falling golf ball strikes the ground and exerts a force on it. Which sentences are true about this situation?
A golf ball striking the ground is a collision.
The ground exerts an equal force on the golf ball.
The ground doesn’t exert a force on the golf ball.
The force is zero because the golf ball has little mass.

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?