Question

A body of mass $2$ kg starts with an initial velocity $5$ m/s. If the body is acted upon by a time dependent force (F) as shown in figure, then work done on the body in $20$ s is?

Answer 1

The graph is given between force and time.

Area under Force-time graph gives Impulse.

So, Total area in 20s is

$A_2=\frac{1}{2}\times 5\times 20=50m^2$

$A_1=20\times 5=100m^2$

$A_3=\frac{1}{2}\times 10\times (-20)=-100m^2$

Therefore total area A=$A_1{+A}_2+A_3$

A= 50$m^2$

Work done W= $F\times s=(F\times t)\times v$

Initial velocity is given, v=$5m/s$

Work done, $W=Ft.v$

W= 50 x 5 J

= 250J