Question

What would be the weight of an object of mass 60 kg on the:

1. the surface of the earth?
2. moon?

Answer 1

Step 1:Given,

$\text{Mass of the body = 60 kg.}$.

Step 2:To find the value of the weight of the body on the surface of earth.

1. Weight of a body is defined as the force with which a body is attracted or pulled towards the centre of the earth.
2. Mass of a body is defined as the total quantity of matter present in the body and is constant throughout the universe including the earth and the moon.
3. When a body is at rest on earth's surface, the same force will pull it down onto earth and this is the force we call its weight and is given by:

$\text{Weight of a body = m × g}$.

$\text{Weight of the body = mass of the body ×acceleration due to gravity}$

= ${\text{60 kg×9.8 m s}}^{-2}=\mathbf{588}\mathbf{}\mathbf{N}\mathrm{.}$

Step 3:

To find the value of the weight of the body on the moon

Acceleration due to gravity on the moon is $\frac{1}{6}\mathrm{th}$ of the gravity exerted by the earth, so the weight of the body on the moon is given by:

$\text{Weight of a body in moon = m × g×}\frac{1}{6}$.

Weight of a body = ${\text{60 kg × 9.8 m s}}^{-2}\text{×}\frac{1}{6}$.

= 98 N

Hence, the weight of the body on the surface of the earth is 588 N, and the weight of the body on the moon is 98 N.