If the work done by a body on application of a constant force is directly proportional to the distance travelled by the body, express this in the form of an equation in two variables and draw the graph of the same by taking the constant force as $5$ units. Also read from the graph the work done when the distance travelled by the body is

$(i)$ $2$ units

$(ii)$ $0$ units

Constant force is $5$ units. Let the distance travelled $= x$ units and work done $= y$ units

since,   Work done $=$ Force $\times$ Displacement 

 $\Rightarrow $                $y=5 \times x$

$\Rightarrow $                $ y=5 x$

Drawing the graph

We have $ y=5 x$

When $x =0,$ then $y =5(0)=0$

When $x =1,$ then $y =5(1)=5$

When $x =1.5,$ then $y =5(1.5)=7.5$

$\therefore $    We get the following table :

$x$	$0$	$1$	$1.5$
$y$	$0$	$5$	$7.5$

Plotting the ordered pairs $(0,\,0)$, $(1,\,5)$ and $(1.5,\,7.5)$ on the graph paper and joining the points, we get a straight line $OB$. 

From the graph, we get

$(i)$ Distance travelled $= 2$ unit

$\therefore $  $x=2$, then  $y=10$ units

$\Rightarrow $ Work done $=10$ units.

$(ii)$ Distance travelled $=0$ units

$\therefore $       $y=5 x \Rightarrow y=5(0)=0$

$\therefore $       Work done $=0$ unit.