Question

A body of mass 3kg is under a constant force which causes a displacement s in metres in it, given by the relation s= 1/3 t^2, where t is in seconds.Work done by the force in 2 seconds is

Answer 1

To find the work done we have to find:
1) Force
2) Displacement
Then after using ;
Work done = Force × displacement .
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# Finding FORCE :
We are given displacement-time relation :
s = (1/3) × t²
Differentiating it wrt time t ; we get velocity - time relation :-
v = (2/3)×t
again differentiating above wrt time t ; we get acceleration of body :-
a = 2/3 m/s²
Now ;
Force = mass × acceleration
= 3× (2/3) = 2 N
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#Finding Displacement
using displacement-time relation and putting the t = 2 ; we get the displacement the body covers in 2 seconds .
s = (1/3) (2)²
s = 4/3 m
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Now work done = 2 × 4/3
= 8/3 J
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hope it helps !

Answer 2

Answer:

hope it helps u sir.........