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Grade 12th PassMechanics

Kinetic energy of a particlemoving in a straight line is proportional to the time t.The magnitude of the force acting on the particle is

a.directly proportional to the speed of the particle

b.inversely proportional to √t

c.inversely proportional to the speed of the particle

d.directly proportional to √t

Plz explain ur answer.

Profile image of Menka Malguri
14 Years agoGrade 12th Pass
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2 Answers

Profile image of Swapnil Saxena
14 Years ago

The option (c) i.e inveresely  proptional to the speed of the partice might be correct.

Let the Kinetic Energy of the particle is = E

Then E = kt (where k is a constant)

At time t=0 , particle Energy =0

Under a variable force its velocity increses from 0 to E in t seconds

Then E= integration of F . ds 

ds can be written as V.dt (velocity) thus E = integration of F . v dt

kt= integration of Fv dt

k.dt= Fv.dt

k= Fv

F= k/v (c.) ----------(ans)


Profile image of ankitesh gupta
13 Years ago

 

 

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