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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)` . Find the force acting on the body at t=2 sec.

A

136N

B

134N

C

158N

D

98N

Text Solution

Verified by Experts

The correct Answer is:
A
Here, `Here, x(t)=pt+qt^(2)+rt^(3)`
`"where p" =3ms^(-1),q=4ms^(-2), r=5ms^(-2) and m=2kg`
`"velocity", v=(dx)/(dt)=(d)/(dt)(pt+qt^(2)+rt^(3))=p+2qt+3rt^(2)`
Acceleration, `a=(dv)/(dt)=2q+6rt`
`""At" t=2s, a=2(4ms^(-2))+6(5ms^(-3))(2s)`
`=8ms^(-2)+60ms^(-2)=68 ms^(-2)`
The force acting on the body of mas 2 kg is
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