Question

A coolie carries a load of 400 N to a distance of 10 m. What is the work done by him?​

Answer 1

Answer:

Given:

Load carried = 400 N

Distance travelled = 10 m

To find:

Work done by him

Concept:

Work done is a scalar quantity represented as the dot product (scalar product) of 2 vectors (i.e. Displacement and Force)

Mathematically , we can say that :

$\boxed{ \huge{ \bold{work \: = \vec f. \vec r}}}$

Let the angle between force and displacement be θ, then we can say that :

$\boxed{ \bold{ \huge{work = f \times r \times \cos( \theta) }}}$

Calculation:

While carrying the luggage , the coolie is exerting a force against gravity and simultaneously travelling forward. So the angle between f and r is 90°

We know that :

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \boxed{ \red{ \bold{ \cos(90 \degree) = 0}}}$

So work done will be :

$\blue{ \bold{ \large{work = f \times r \times \cos( 90 \degree) }}}$

$\blue{ \bold{ \large{ = > work = f \times r \times(0) }}}$

$\blue{ \bold{ \large{ = > work = 0 \: joule}}}$

Answer 2

$</p><p>\tt{\huge{\pink{Hello!!!! }}}$

The F.B.D is in the attachment.

___________

We Know That :

$</p><p>\tt{\orange{\huge{Work\: Done \: = F \times R \times cos \phi}}}$

While carrying the luggage , the coolie is exerting a force against gravity and simultaneously travelling forward. So the angle between f and r is 90°.

We know that the value of cos(90°) = 0.

Hence, for any Mass and any distance travelled, the work done is 0.