Question

Find out the work done when a force of 40 N
displaces a body through 5 m in the direction of applied force.
[Ans. 200 ]
​

Answer 1

Topic

Work, Power and Energy

To Find

Total work done in given situation.

Given

A force of 40N displaces a body through 5 metres in the direction of applied force.

Formula

$\boxed{\sf{W = Fscos\theta}}$

where

• W = Total Work Done

• F = Applied Force

• s = Displacement

• $\theta$ = Angle between Force and Displacement

Solution

Force applied = 40 N

Displacement = 5 metres

$\theta = 0^{\circ}$ because Displacement is in direction of Force.

cos( 0 ) = 1

Now,

Applying the Formula,

W = Fscos$\theta$

W = 40N × 5m × 1

W = 200 Joules

Answer

So, work done by the body is 200 Joules.

Note :-

Always take care of direction of Force and displacement. If they are in same direction then $\theta$ is equal to zero and if they are in opposite direction $\theta$ is equal to $180^{\circ}$.

Answer 2

Given :

• $\sf Force = F = 10 N$

⠀⠀⠀⠀

• $\sf Distance = S = 5m$

⠀⠀⠀⠀

• $\sf Angle of displacement = \theta = 0^{\circ}$

To Find :

⠀⠀⠀⠀

• $\sf Work \: done = ??$

⠀⠀

Solution :

⠀⠀⠀⠀

$\bigstar\:{\underline{\sf Using \: expression \: for \: work \::}}$

⠀⠀⠀⠀

$\sf :\implies{\underline{\boxed{\bold{\pink{ W = F \times S cos \theta}}}}}\bigstar$

⠀⠀⠀⠀

⠀⠀⠀⠀

$:\implies\sf W = 40 N \times 5m \times Cos 0^{\circ}$

⠀⠀⠀⠀

$:\implies{\underline{\boxed{\bold{\pink{Cos.\theta = 1 }}}}}$

⠀⠀⠀⠀

$:\implies\sf W = 40 N \times 5m \times 1$

⠀⠀⠀⠀

$:\implies\sf W = 200 Joules$

⠀⠀⠀⠀

⠀⠀⠀⠀

$:\implies{\underline{\boxed{\frak{\purple{W = 200 \:J}}}}}\;\bigstar$

⠀⠀⠀⠀

$\therefore\:{\underline{\sf{Total\;work\;done\; by \:body \: is \; \bf{200\:J}.}}}$

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