Question #e2a90

1 Answer
Feb 3, 2017

8(1+t)" Js"^-18(1+t) Js1

Explanation:

We know that Kinetic Energy of an object having mass mm and velocity vv is given by the expression

KE=1/2mv^2KE=12mv2 .....(1)

Also kinematic equation connecting quantities of interest is

v=u+atv=u+at.....(2)
where uu is initial velocity, a and taandt are acceleration and time respectively.
Inserting value of vv from (2) in (1) we get
KE=1/2m(u+at)^2KE=12m(u+at)2

To find rate of change of kinetic energy we differentiate both sides with respect to time. We get

dot(KE)=d/dt[1/2m(u+at)^2].KE=ddt[12m(u+at)2]

using chain rule we get
dot(KE)=1/2m[2(u+at)xxa].KE=12m[2(u+at)×a]

Inserting given values we get
dot(KE)=1/2xx2[2(2+2t)xx2].KE=12×2[2(2+2t)×2]
dot(KE)=8(1+t)" Js"^-1.KE=8(1+t) Js1