Question

The displacement-time graph of a body acted upon by some forces is shown in figure. For this situation, match the entries of Column I with the entries of Column II.

Column I		Column II
i	For , the total work done by all forces together is	a	always positive
ii	For , the work done by few of the acting forces is	b	can be positive
iii	For , the work done by few of the acting forces is	c	zero or can be zero
iv	For , the work done by all forces together is	d	can be negative

• A. i a; ii b, c, d; iii b, c, d; iv c
• B. i b; ii c; iii a; iv c
• C. i d; ii c; iii a; iv a
• D. i b; ii c; iii d; iv a

Answer 1

Answer: (A)

In , velocity increases, hence increases. So overall work done is positive. If a number of forces are acting on the body, then it is possible that some forces do positive work, some negative and some zero.
In , velocity is constant, hence there is no change in . So net work done by all the forces is zero.