Question

Sasha lifts a couch 8.2 meters from the ground floor of her house to the attic. If the couch has a mass of 120 kg, what is the gravitational potential energy gained by the couch? Estimate g as 9.81 m/s^2. (Answer in Joules)

Answer 1

As we know that gravitational potential energy is given by

$U = mgH$

here we have

m = mass = 120 kg

$g = 9.81 m/s^2$

h = height = 8.2 m

now from above formula

$U = 120kg (9.81 m/s^2) (8.2 m)$

$U = 9653.04 J$

so above is the gravitational potential energy of the couch

Answer 2

Given data:

height of cough from ground floor (h) = 8.2 m,

                         mass of the cough (m) = 120 kg,

find gravitational Potential energy (U) =?

            acceleration due to gravity (g) = 9.81 m/s²

Gravitational potential energy is defined as "the energy possessed by an object because of its position in the gravitational field".  This principle can be applied to objects that are over the earth's surface and gravitational constant assumed to be 9.81 m/s².

Gravitational potential energy also defined as work done in moving the object  from infinite to a particular point by the effect of gravity.

Therefore, mathematically

          Grvitational Potential energy

                                 U = m.g.h  Joules

                       where,

                                   m= mass of object in kg

                                   g = gravitational constant in m/s² (g=9.81 m/s²)

                                   h = height of the object from ground in m

                                   U = 120 kg × 9.81 m/s²× 8.2 m

                                    = 9653.04 J

The gravitational potential energy is 9653.04 Joules