Question

3. A force acts for 5secs on a body which is at rest. The body moves through a distance
of 100m in the next 10secs after the force ceases to act. Find :-
a) the velocity acquired by the body
b) the acceleration produced
the magnitude of force applied if the mass of the body is 4kg.​

Answer 1

Given:-

• Initial velocity ,u = 0m/s

• Time taken ,t = 5 s

• Distance travelled ,s = 100m

• Time taken ,t' = 10s

To Find:-

• The velocity acquired by the body,v

• The acceleration produced ,a

• The magnitude of force applied if the mass of the body is 4kg ,F

Solution:-

(a)

Using 1st equation of motion

• v = u+at

Substitute the value we get

→ v = 0 + a×5

→ v = 5a ----------(i)

Now,

Distance travelled 100metres

• S = vt

→ 100 = 5a × 10

→ a = 100/50

→ a = 2m/s²

Therefore, the acceleration of the body is 2m/s².

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(c)

Now , We know that Force is the Product of mass and acceleration.

• F = ma

Substitute the value we get

→ F = 4 × 2

→ F = 8 N

Therefore, the magnitude of force is 8 Newton.

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Putting the value of a in Equation (i) we get

→ V = 5a

→ V = 5×2

→ V = 10m/s

Therefore the velocity of the body is 10m/s.