Question

A coolie is walking on a railway platform with a load of 27kg on his head what is the amount of work done by him

Answer 1

Answer:

the work done will be zero in respect to the 90 degree angle formed from the displacement

Answer 2

Given:

Mass of load = 27 kg

To find:

Work done by coolie for carrying the load from one point to another.

Explanation:

• Work done is the force applied on an object that makes the object make a sense of movement.

• Mathematically, work done is the dot product of force and the displacement produced by the object.

                         W = F . r

                         W = F r cosθ

Where, θ is the angle between the direction of force applied and the     direction of displacement produced.

Solution:

In the question we have been given that the coolie lifts the weight on his head. Hence, the weight of the load (mg) is directed downwards towards the ground.

The coolie has to do the work to keep it upwards and put force not to collapse under the load's weight. Hence, work done by the coolie is directer in the upwards direction.

And, we have also been told that he is moving forward, therefore the angle made by the force applied by coolie and the direction of displacement is perpendicular (90°).

Therefore,

Applying this is the equation of work done, we get

W = (mg) (r) cosθ

W = (27)(10)(r) cos90°

We know, cos 90° = 0

Therefore,

W = 0 J

Final answer:

Hence, work done by coolie in moving a load 27 kg is 0J.