A cinder block is sitting on a platform 20m high. It weighs 7.9kg. The block has potential energy. calculate it

By definition, the potential energy is

U = m * g * h

Where

m = mass

g = accelecarion of gravity

h = height

Substituting

U = (7.9) * (9.8) * (20) = 1548.4J

The block has a potential energy of 1548.4J

Note: assuming reference level on the ground

The formula for potential energy is mass * gravity * height. With height given as 20m and weight given as 7.9kg, we can fill in 7.9 * gravity * 20. Gravity is 9.8m/s constant so 7.9 * 9.8 * 20 = potential energy. The result is 1549.45, with the unit of energy being joules. Final answer 1549.45 J