Question

1. what happens as the pendulum moves from its highest point to its lowest point? a. potential energy increases and kinetic energy decreases? b. both potential and kinetic energy stay the same c. potential energy changes into kinetic energy d. the pendulum loses all its energy.

Explanation:

To solve this, we recall the concepts of potential and kinetic energy. Potential energy (PE) depends on height ($PE = mgh$), and kinetic energy (KE) depends on velocity ($KE=\frac{1}{2}mv^2$). At the highest point (A or C), the pendulum has maximum PE (due to height) and minimum KE (velocity is 0). As it moves to the lowest point (B), the height decreases, so PE decreases. The velocity increases (since it's accelerating downwards), so KE increases. This means PE is converted into KE.

• Option A is wrong because PE should decrease and KE increase.
• Option B is wrong as energies change.
• Option D is wrong because energy is conserved (ignoring air resistance), so it doesn't lose all energy.

Answer:

C. Potential energy changes into kinetic energy