Question

1-20N ;2-15N;3-10N;4-30N

Answer 1

Answer

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The Force continues to provide the desired acceleration to the body for 10 sec and the body gains some Velocity

Assuming Initially the body was at rest

Displacement (s) = 50 m

Time (t) = 5 sec

Let Retardation after Force stops on body be r

Putting it in 2rd eqn of Motion,

s = ut - 1/2 r t^2

s = 0 - 1/2 x r x 25

50 = -12.5 r

r = -4 m/sec^2

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Putting this in 1st eqn of motion,

v = u + rt

0 = u - 20

=> u = 20 m/sec

The Concept is applied here where the Initial velocity is the Velocity at the instant when the force was removed

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In case of duration till which force was applied

u = 0 ; v = 20 ; t = 10 ; m = 10

We know,

$F = \frac{m(v-u)}{t}$

We get F = 20 N

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HOPE IT HELPS :):):)

BRAINLYY