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An object of mass 3 kg is at rest. Now...

An object of mass ` 3 kg ` is at rest. Now a force of ` vec F = 6 t^2 hat I + 4 t hat j` is applied on the object, the velocity of object at `t= 3 s` is.

A

`18hatj+3hatj`

B

`18hati+6hatj`

C

`3hati+18hatj`

D

`18hati+4hatj`

Text Solution

Verified by Experts

The correct Answer is:
B
`veca=vecF/m=2t^2hati+4/3thatj`
`dvecv=(2t^2hati+4/3thatj)dt`
Integrate on both sides
`vecv=2[t^3/3]hati+4/3[t^2/2]hatj` at t=3 sec. `vecv=2/3(3)^3 hati+4/6(3)^2 hatj`
=`18 hati+6 hatj`
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