Question

A equilateral triangle is formed using 3 wires, AB, BC and CA. They are placed in a vertical plane such that AB is parallel to earth's surface. Coefficient of friction for all the three wires is the same. If w_1 and w_2 are the work done by friction in moving the object from A to B along AB and ACB then:

• w_1=w_2
• w_1 > w_2
• w_1 < w_2
• Can't say

Question shared by Siddhant Chawla

Solution

This is pretty straight forward question, you just need to calculate the work done by friction when moving in a straight line AB and when moving along ACB

The work done in AB is: w_1=muxxmgxxa

The work done in ACB is: w_2=muxxNxxa+muxxNxxa

=muxxmgcos60xxa+muxxmgcos60xxa

=muxxmgxxa

So the work done by friction along AB is equal to work done along ABC