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A body of mass 2kg travels according to ...

A body of mass `2kg` travels according to the law `x (t) = pt + qt^(2) + rt^(3)` where `p = 3ms^(-1),q = 4 ms^(-2)` and `r = 5ms^(-3)` .

A

`136N`

B

`134N`

C

`158N`

D

`68N`

Text Solution

Verified by Experts

The correct Answer is:
a
Here, `m = 2kg`
`x (t) = pt + qt^(2) + rt^(3)`
`upsilon = (dx)/(dt) = p + 2 qt + 3rt^(2)`
`a = (d upsilon)/(dt) = 0 + 2q + 6rt`
As `t =2 sec, a = 2q + 12 r = 2xx4 + 12 xx5 =68m//s^(2)`
`F =ma = 2 xx 68 N = 136 N` .
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