Question
1. Jane, looking for Tarzan, is running at top speed (4.9m/s) and grabs a vine hanging vertically from a tall tree in the jungle. How high can she swing upward?
2. In the high jump, Frank's kinetic energy is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must Fran leave the ground in order to lift her center of mass 1.89m and cross the bar with a speed of 1.16m/s?
3. A 57kg trampoline artist jumps vertically upward from the top of a platform with a speed of 4.7m/s. How fast is he going as he lands on the trampoline 3.8m below?
4. A 124g baseball is dropped from a tree 11.6m above the ground. With what speed would it hit the ground if air resistance could be ignored?
2. In the high jump, Frank's kinetic energy is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must Fran leave the ground in order to lift her center of mass 1.89m and cross the bar with a speed of 1.16m/s?
3. A 57kg trampoline artist jumps vertically upward from the top of a platform with a speed of 4.7m/s. How fast is he going as he lands on the trampoline 3.8m below?
4. A 124g baseball is dropped from a tree 11.6m above the ground. With what speed would it hit the ground if air resistance could be ignored?
Answers
gain of of kinetic energy at low spot = loss of potential energy coming down from top
(m/2)(Vbottom^2 - Vtop^2) = m g (meters down from top)
or if stopped at top
(1/2)m v^2 = m g h
or (remember this) v = sqrt (2 g h)
(m/2)(Vbottom^2 - Vtop^2) = m g (meters down from top)
or if stopped at top
(1/2)m v^2 = m g h
or (remember this) v = sqrt (2 g h)