Q7 of 42 Page 29

A body of mass 2kg travels according to the law x(t) = pt + qt2 + rt3

Where p = 3 m s-1, q = 4 m s-2 and r = 5 m s-3.


The force acting on the body at t = 2 seconds is


We have given in question x(t) = pt + qt2 + rt3 so to find the force we will differentiate above position equation two times i.e.

We have where


So


Now first derivative of above equation




t=2


Hence


Therefore, option (a) is correct.

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