Question

A heavy box of 40 kg is pushed along 20 m by two coolies over a railway platform whose cofficent of fircition with the box is 0.4 the work done by the two coolies take g=10 and assume force applied to be horizontal

Answer 1

Answer:

3200J

Explanation:

umg≈F is the force applied.

So F= 400N

Work done = 400x20= 3200 Joule

Answer 2

Answer:

3200J

Explanation:

Since the  box is moving so maximum friction acts i.e, f=μmg

And force by coolies overcomes the friction F=f

Therefore the work by coolies=F.s=μmgs

Or W=μmgs=0.4×40×10×20J

W=3200J, hence Option C is correct