Question

A particle of mass 0.01 kg travels along a curve with velocity given by $4 \hat { i } + 16 \hat { k }$ms^-1. After some time, its velocity becomes due to the action of a conservative force. The work done on particle during this interval of time is

• A. 0.32 J
• B. 6.9 J
• C. 9.6 J
• D. 0.96 J

Answer 1

Answer: (D)

0.96 J

Answer 2

$v _ { 1 } = \sqrt { 4 ^ { 2 } + 16 ^ { 2 } } = \sqrt { 272 }$ and

$v _ { 2 } = \sqrt { 8 ^ { 2 } + 20 ^ { 2 } } = \sqrt { 464 }$

Work done = Increase in kinetic energy

.