Answer:
A. ) K =126. 7 J
B. ) h= 91.1 m.
Explanation:
A)
- Assuming no air resistance, once released by the pitcher, the speed must keep constant through all the trajectory, so the kinetic energy of the ball can be expressed as follows:
B)
- Neglecting air resistance, total mechanical energy must be the same at any point, so, if we choose the ground level as the zero reference level for the gravitational potential energy, and assuming that the ball attains this kinetic energy just before striking ground, this value must be equal to the gravitational potential energy just before be dropped, so we can write the following equality:
⇒ m*g*h = 126. 7 J
- Solving for h, we get: