A particle which is experiencing a force, given by `vec(F) = 3 vec(i) - 12 vec(j)`, undergoes a displacement of `vec(d) = 4 vec(i)`. If the particle had a kinetic energy of 3 J at the beginning of the displacement

Options

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

Answer

C

Explanation

Work done by a force = Change in kinetic energy `(DeltaK.E.)`
`implies Delta K.E. = vecF cdot vecd = (3 hati - 12 hatj) cdot (4 hati) = 12J " " implies K_(f) = (K_i + 12)J = 15J`.