Question

9. A force acts for 0.1 s on a body of mass 2.0 kg
initially at rest. The force is then withdrawn and
the body moves with a velocity of 2 ms. Find
the magnitude of force.
​

Answer 1

Answer :-

20N

Explanation :-

Given :

Time = 0.1s

Mass = 2.0kg

Initial velocity = 0m/s     [as body was initially at rest]

Final velocity = 2m/s

To Find :

Force = ?

Solution :

According to the first equation of motion,

$\boxed{\sf{}v=u+at}$

where,

v is the final velocity,

u is the initial velocity,

a is the acceleration and,

t is the time taken.

$\sf{}\implies 2=0+a\times 0.2$

$\sf{}\implies 2=a\times 0.2$

$\sf{}\implies \dfrac{2}{0.2}=a$

$\sf{}\therefore a=10m/s^2$

Now we the acceleration, so let’s find out the force,

We know,

$\boxed{\sf{}F=ma}$

where,

F is the force applied,

m is the mass,

a is the acceleration.

Put their values and find “F”

$\sf{}\implies F=2\times 10$

$\sf{}\therefore F=20N$

Therefore,force applied is equal to 20N