The velocity of a 2 kg body is changed from `(4hati +3hatj)` `ms^(-1)` to `6hat ms^(-1)`. The work done on the body is

Options

A. 9 J
B. 11 J
C. 1 J
D. 0 J

Answer

b

Explanation

Here velocity
`v_1=sqrt((4)^2+(3)^2)=5 ms^(-1)`
and velocity `v_2=6 ms^(-1)`
Now W=increase in K.E.
`=1/2m(v_2^2-v_1^2)`
=`1/2xx2(36-25)`
=11 J