Question

A salami sandwich is dropped from the top of a 37 m tall construction crane. What is the speed of the sandwich when it is halfway to the ground?

(Use conservation of energy!)

Answer 1

Ek + Ep = mg*37.
Ek + mg*18.5 = mg*37
Ek = mg*37 - mg*18.5 = mg*18.5
Ek = 0.5m*V^2 = mg*18.5
V^2 = mg*18.5/0.5m = 2g*18.5 = 19.6*18.5
= 363 Joules.
V = 19 m/s.

Ek = Kinetic energy.
Ep = Potential energy.

Answer 2

Correction
V^2 = 363 (m/s)^2. NOT 363 Joules.