A force of 40 N is applied on a body so that it attains a velocity of 20 m/s in 5 s. What is the mass of the body?

Let m (kg) = the mass of the body.

The body attains a velocity of 20 m/s in 5 s. Therefore the acceleration is

a = (20 m/s) / (5 s) = 4 m/s².

Note that

F = ma

where

F = applied force,

a = acceleration,

m = mass

The applied force is 40 N, therefore

(m kg) * (4 m/s²) = 40 N

m = 40/4 = 10 kg

Answer: 10 kg