• # question_answer Power applied to a particle varies with time as $P=\left[ 3{{t}^{2}}-2t+1 \right]$ watts. Where t is time in seconds. Then the change in kinetic energy of particle between time $t=2s\text{ }to\text{ }t=4s$ is- A) 46 J                             B) 52 JC) 92 J                             D) 104 J

$P=3{{t}^{2}}-2t+1~~~\,\,\,P=\frac{Ek}{t}=3{{t}^{2}}-2t+1$ $K.E.\left( 3{{t}^{2}}-2t+1 \right)\,\,\,dt=\left( {{t}^{3}}-{{1}^{2}}+t \right)_{2}^{1}=46\,J$