Question

A 75-kg piano is hoisted on a crane and delivered through the window of a 6th-story apartment (20 meters above the ground). What is the potential energy of the piano?

Answer 1

Answer:

p=14700 j

Explanation:

Given that,

Mass of a piano, m = 75 kg

It is delivered throughout the window of a 6th story apartment which is 20 m above the ground.

We need to find the potential energy of the piano. It is given by :

P = mgh

Putting all the values,

P = 75 kg × 9.8 m/s² × 20 m

P = 14700 J

So, the potential energy of the piano is 14700 J.

Answer 2

Given:

Mass of piano = 75 kg.

Height = 20 metres.

To find:

Potential Energy of piano ?

Calculation:

Potential Energy is a type of mechanical energy by the virtue of its position with respect to the reference frame.

Here, Gravitational Potential Energy is:

$PE = m \times g \times h$

$\implies \: PE = 75 \times 10 \times 20$

$\implies \: PE = 15000 \: joule$

$\implies \: PE = 15 \: kilojoule$

So, potential energy of piano is 15 kJ.