Chapter 8 Physics for engineering and scientist?

[shaniquahgarvin_2001]

1.)A 0.395 kg ball is thrown straight up into the air and reaches a maximum altitude of 20.4 m.
(a) Taking its initial position as the point of zero potential energy and using energy methods, find its initial speed.
m/s
(b) What is its total mechanical energy?
J
(c) What is the ratio of its kinetic energy to the potential energy of the ball-Earth system when the ball is at an altitude of 6.80 m?

2.)A simple 2.08 m long pendulum is released from rest when the support string is at an angle of 24.3° from the vertical. What is the speed of the suspended mass at the bottom of the swing?
m/s