A 61 kg engineer leaves her office on the 33rd floor of a skyscraper and takes an elevator up to the 59th floor. Later she descends to street level. The engineer takes the zero of potential energy at street level and the distance from one floor to the next is 3.5 m.

What is the engineer's potential energy in her office?

Ep = 69045.9 J

Explanation:

Potential energy

We define gravitational potential energy as the energy that a body possesses due to the fact of being under the action of gravity. Its value, in the case of small heights above the earth's surface, is given by:

Ep = m*g*h Formula (1)

Where:

Ep: It is the potential energy of the body. (J)

m: Body mass. (kg)

g: Acceleration value due to gravity (m/s²)

h: Height at which the body is on the surface of the earth (m)

Data

m = 61 kg : mass of the engineer

h = 33 * 3.5 m = 115.5 m : floor height of the office of the engineer

g = 9.8 m/s²

Engineer's potential energy in her office

Ep = m*g*h

Ep = (61 kg) * (9.8 m/s²) * (115.5 m)

Ep = 69045.9 (kg * (m/s²)) * (m)

Ep = 69045.9 N*m

Ep = 69045.9 J