8. A ball of mass m= 6 kg is dropped from a height (hi = 10 m) above the ground. Find the speed of the ball when it is at a height (h = 4 m) above the ground. h=10m h= 4 m 8 9. A 25 kg crate slides down a ramp. The ramp is 2 min length and inclined at an angle of 30 as shown in Figure. The crate starts from rest at the top, experiences a constant friction force of magnitude 6 N, and continues to move a short distance on the horizontal floor after it leaves the ramp. V; =0 d = 2 m 1 m 30.0 a. Use energy methods to determine the speed of the crate at the bottom of the ramp. b. How far does the crate slide on the horizontal floor if it continues to experience a friction force of magnitude 4 N?