Question

Look at the activity listed here. Reason out whether or not work is done in the light of your understanding of the term 'work'.

A sailboat is moving due to wind energy.

Answer 1

Step 1: Work Done

1. Work done is a scalar quantity.
2. Force and displacement are vector quantities.
3. We know that the dot product of two vectors gives a scalar quantity as its result.
4. Work done is defined as the force applied to displace a body from its original state.
5. Therefore work done is the dot product of force and displacement.

If $\overrightarrow{F}$ is the force applied and $\overrightarrow{S}$ is the displacement of the body, then the work done $W$ can be given as,

$W=\overrightarrow{F}.\overrightarrow{S}$

$=FS\cos \theta$

where, $\theta$ is the angle between the direction of force vector and displacement vector.

Step 2: Check if work is done

1. A sailboat can sail, when the wind pushes it in the forward direction.
2. So, the force applied and the displacement occur in the same direction.
3. Hence, the work is done on a sailboat by the wind when it is moving due to wind energy.