2) A pendulum is made from a 7.50-kilogram mass attached to a rope connected to the ceiling
of a gymnasium. The mass is pushed to the side until it is at position A, 1.5 meters higher
than its equilibrium position. After it is released from rest at position A, the pendulum moves
freely back and forth between positions A and B, as shown in the diagram below.
Ceiling
7.50 kg
B
11.5 m
Equilibrium
position
What is the total amount of kinetic energy that the mass has as it swings freely through its
equilibrium position? [Neglect friction.]

110 J

Explanation:

Conservation of Energy: the PE that the pendulum mass has at the highest point equals the kinetic energy that it has moving through the squilibrium position.

ΔPE= mgΔh

ΔPE= (7.50 kg)(9.81 m/s^2)(1.5 m)= 110J

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )