Question

velocity-time graph of a particle of mass 2 kg moving in a straight line is as shown in Fig. 6.19. Find the work done by all the forces acting on the particle.

• A. -200 J
• B. -400 J
• C. -600 J
• D. -700 J

Answer 1

The correct option is B -400 J

Acceleration of the particle = $a=\frac{\Delta v}{\Delta t}$

$=\frac{-20}{2}=-10m/s^2$

Distance travelled by particle before coming to rest=Area of the triangle=$\frac{1}{2}\times 2\times 20m=20m$

Thus the work done by forces=$Fs=mas$

$=2\times -10\times 20J=-400J$