Question

A 75kg refrigerator is located on the 70th floor of a skyscraper (300m above ground). What is the potential energy of the refrigerator?

Answer 1

Given:

A 75kg refrigerator is located on the 70th floor of a skyscraper (300m above ground).

To find:

Potential energy of the object at that height.

Calculation:

• Potential energy is a type of mechanical energy possessed by a body by the virtue of its distance from a reference point.

• Gravitational Potential Energy can be calculated by the product of mass of object , gravitational acceleration and height from reference.

$\rm{ \therefore \: P_{g} = m \times g \times h}$

$\rm{ = > \: P_{g} = 75\times 10 \times 300}$

$\rm{ = > \: P_{g} = 225000 }$

$\rm{ = > \: P_{g} = 225 \times {10}^{3} \: joule }$

$\rm{ = > \: P_{g} = 225 \: kilojoule }$

So, potential energy of the refrigerator at that height is 225 kJ.

Answer 2

Answer: 220725J

Explanation:

They are looking for the potential energy so we going to use the equation PE=mgh since they provided the mass , height and g

m=75g
h=300
g=9.81
PE= ?

                                                      The equation used : PE=mgh
                                                      PE=(75)(9.81)(300)
                                                      =220725J