Question

A women pushes a trunk on a railway platform which has a rough surface.She applies a force of

100 N over a distance of 10m. There after, she get progressively tired her applied force reduces

linearly with a distance of 50 N. Total distance which the trunk has been moved is 20m.Plot the

force applied by the woman and the frictional force which is 50 N versus displacement.Calculate

the work done by the two forces over 20 m.​

Answer 1

Explanation:

The plot of the forces applied b the woman and the frictional forcesf versus displacement is,

x=20m,f=50N(



=0)

Since we have f=∣f∣=50N

It opposes the motion and acts in the direction opposite to f,

So, the negative side of the force axis,

The work-done by the woman is:

W

f

=area of rectangle ABCD+area of trapezium CEID

W

f

=1000×10+

2

1

(1000+50)×10

1000+750=1750J

Now, the work done by the frictional force is:

Area of the rectangle AGHI

W

f

=(−50)×20=1000N

thank you.. hope it helps