In the above question what is the force acting after 2 sec ?

Options

A. `(4overset(wedge)(i)+8overset(wedge)(j))N`
B. `(4overset(wedge)(i)+4overset(wedge)(j))N`
C. `(8overset(wedge)(i)+8overset(wedge)(j))N`
D. `(6overset(wedge)(i)+6overset(wedge)(j))N`

Answer

a

Explanation

Here`vecupsilon=(2thati+t^(2)hatj)`
`:.veca=(dvecupsilon)/(dt)=2hati+2thatj`
Now at 2 `sec veca_(t)=(2hati+4hatj)`
`vecF=2(2hati+4hatj)`
`=(4hati+8hatj)N`
Hence (a) is the right choice.