If the work done by a body on applying a constant force is directly proportional to the distance travelled by the body, then express this in the form of an equation in two variables by taking the constant force as 4 units. From the graph, find the work done when the distance travelled is (i) 2 units (ii) 0 units (iii) 5 units.

Work done = W

Force = F = 4

Distance = d

Since, Work done ∝ Distance

Therefore, W ∝ d

⇒ W = F× d

⇒ W = 4d

Let d = 0

⇒ W = 4 × 0 = 0

Let d = 2

⇒ W = 4 × 2 = 8

Let d = 5

⇒ W = 4 × 5 = 20

Plotting them we get the following graph,

The blue line indicates the required graph of W = 4d

Clearly from the graph,

(i) When d = 2 units

then, W = 8 units

(ii) When d = 0 unit

then, W = 0 unit

(iii) When d = 5 units

then, W = 20 units