#### Work Done When Lifting Objects

_{2}above ground, against gravity.

**h**) he lifts the weights against gravity.

Recall that the force of gravity Fg = m x g

Therefore, the work done in lifting an object against gravity can be calculated using the equation

*W = m x g x h*

Example

What is the work done by an elevator on 5 people (800 Kg) inside the elevator, if they all get off on the 4th. floor (12 m above the ground)?

Solution:

Given:

m = 800 Kg, g = 9.8 N/Kg, h = 12 m

Find: W

W = m x g x h

= 800 Kg x 9.8 N/Kg x 12 m

= 94080 Nm

= 94 080 J

Therefore, the work done in lifting an object against gravity can be calculated using the equation *W = m x g x h*

*Example 2:*

*What is the work done by an elevator on 5 people (800 Kg) inside the elevator, if they all get off on the 4th. floor (12 m above the ground)?*

**Solution:**

Given:

m = 800 Kg, g = 9.8 N/Kg, h = 12 m

Find: W

W = m x g x h

= 800 Kg x 9.8 N/Kg x 12 m

= 94080 Nm

= 94 080 J