Conservation of Energy Word Problem

Question

A pendulum swings back and forth. At position “A” (which is the maximum height) it has 140 J of energy. The mass of the pendulum is 3.8kg. What is it’s vertical elevation from its lowest point at point A? What is its velocity at point “B” (the lowest point)?

Answer 1

Hi Mary H.,

Just apply the few formulae you already know(?): E=mgh for the gravitational potential energy (at highest point), and E=(1/2)mv² for kinetic energy at the lowest & fastest position. v here acts like speed, for technical reasons -- all right, if you square a vector you end up with a scalar anyhow -- although in expressions for momentum, it is a full-court-press vector.

-- Cheers, --Mr. d.