Question

For the path PQR in a conservative force field (fig.), the amount of work done in carrying a body from P to Q and from Q to R are 12J and 5J respectively. The work done in carrying the body from $P$ to $R$ will be (in joule)

• A. 7 J
• B. 10 J
• C. 17 J
• D. 15 J

Answer 1

Answer: (C)

17 J

Answer 2

In a conservative force field, the work done is path-independent. Therefore, the work done in moving from point P to point R is the sum of the work done from P to Q and from Q to R.

$W_{PR} = W_{PQ} + W_{QR}$ $W_{PR} = 12 \, \text{J} + 5 \, \text{J} = 17 \, \text{J}$

Thus, the work done in carrying the body from P to R is 17 J.