Question

A force acting on a particle of mass 200 g displaces it through 400 cm in 2 s. If the initial velocity of
particle is zero, then the magnitude of the force is
a) 0.4 N
b) 4N
c) 40 N
d) 400 N


PLEASE SAY THE ANSWER...​

Answer 1

If the initial velocity of the particle is zero then acceleration is,

a = 2s/t^2

Here, 

s=400 cm=4 m and t=2 s. 

So we have,

a=2×4/2^2=2

Now,

mass m=200 g = 0.2 kg.

So force f=ma=0.2×2=0.4 N

Answer 2

Concept:

We need to apply the third kinematic equation, s = ut + 1/2 at² to determine acceleration that would help to calculate the magnitude of force.

Given:

Mass of the particle = 200 g

Displacement = 400 cm

Time taken = 2 seconds

The initial velocity of the particle is zero

Find:

We need to find out the magnitude of the force

Solution:

First, we need to determine the acceleration of the particle. To do that we need to apply the third kinematic equation represented as-

s = ut + 1/2 at² where s is the distance, u is the initial velocity, t is the time and a is the acceleration

We have, s as 400 cm = 4m, u = 0, t = 2s

Therefore, the third kinematic equation of motion becomes-

4 = 0(2) + 1/2a(2)²

Therefore, 4 = 1/2a(4)

4 = 2a

a = 2 m/s²

We know, that Force = mass × acceleration

F = ma where m = 200g = 0.2kg and a = 2m/s²

Therefore, the equation of force becomes-

F = 0.2 × 2

F = 0.4 N

Thus, the correct answer is an option (a). The magnitude of the force is 0.4N.

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