Question

a body of mass 3 kg decreases its speed uniformly from 40 m/s to 10 m/s find the retarding force

Answer 1

F =mass × Acceleration
mass= 3kg
Accerleration =v-u/t
But to find acceleration we should know the time taken which is not given.

Answer 2

Hey there!

Mass of the body, m = 3kg

Initial velocity, u = 40 m/s

Final velocity, v = 10 m/s

We know that,

Retarded force = Force
&

Force = Mass × Acceleration

Here,
Mass is Given, not Acceleration

To calculate Acceleration (a)
We can use the Eqn. of Motion :


v = u + at

or

v² = u² + 2as

But, We are neither given the distance travelled (s) nor time (t)
So we can't calculate Acceleration.

Therefore, retarded force can't be calculated...

HOPE IT HELPED YOU ^_^