Question

A 4 kg mass is travelling with a constant speed of 5 m s -1. It is brought to rest in 2 seconds. The average force acting on the mass to bring it to rest is?

Answer 1

Answer:

A 4 kg mass is traveling with a constant speed of 5 m/s It is brought to rest in 2 seconds. The force acting on the mass to bring it to rest is $10N$

Explanation:

• Newton's second law provides a relation between the mass of a moving body (m), the corresponding acceleration(a), and the applied force(F) as

                               $F=ma$

• The acceleration is the change in velocity divided by the time taken

                               $a=v/t$

From the question, we have

mass of the body $m=4kg$

the velocity of the body $v=5m/s$

time taken to bring the mass in rest $t=2s$

rest means final velocity is zero

so the change in velocity $v-0=5m/s$

therefore the acceleration $a=5/2=2.5m/s^{2}$

⇒the  force acting on the body $F=2.5*4=10N$