Question

A particle which is experiencing a force, given by $\overrightarrow{F}=3\overrightarrow{i}-12\overrightarrow{j}$, undergoes a displacement of $\overrightarrow{d}=4\overrightarrow{i}$. If particle had a kinetic energy of 3 J at the beginning of the displacement, what is its kinetic energy at the end of the displacement ?

• A. 15 J
• B. 10 J
• C. 12 J
• D. 9 J

Answer 1

Answer: (A)

15 J

Work done = $\overrightarrow{F}.\overrightarrow{d}$
= $12J$
work energy theorem
$w_{net}=\Delta K.E.$
$12=K_f-3$
$K_f=15J$