Question

calculate the work done by a person in lifting a load of 20 kg from the ground and placing it on a 1 m high table

Answer 1

m = 20 kg

h = 1 m

 

Work done against gravitational force,

 

W = mgh

    = 20 x 9.8 x 1

    = 196 J

Answer 2

Answer:  

The work done by a person to lift the load of 20 kg from ground to a table of height 1 m is 196J.  

Solution:

The given quantities are the  

Mass of the load m = 20 kg

Height h = 1 m

As the load is taken from the ground and placed on a table, the acceleration due to gravity will be exerted by the body.

The work done is the product of force and displacement.

Force is the product of mass and acceleration which in this case is acceleration due to gravity.

$\bold{\text { Work done }=\text { Force } \times \text { Displacement }}$

$\text { Work done }=m g h=20 \times 9.8 \times 1=196 \mathrm{J}$

Thus the work done to lift the load is 196J.