# Q. A particle which is experiencing a force, given by $\vec{F} = 3\vec{i} - 12 \vec{j}$ , undergoes a displacement of $\vec{d} = 4\hat{i}$ . If the 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 ?

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Solution:

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

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