Question

A force of $1000 \,N$ is applied on a body of mass $100\, kg$ moving with the velocity of $5\, m/s$. How much time does it require to attain a velocity of $25\, m/s$ ?

• A. 8 s
• B. 6 s
• C. 4 s
• D. 2 s

Answer 1

Answer: (D)

From Newtons second law of motion,
$ F=ma $ where m is mass and a is acceleration.
Given, $ F=1000\,N,\,m=100\,kg $
$ \therefore $ $ a=\frac{1000}{100}=10\,m/{{s}^{2}} $
From equation of motion,
we get $ v=u+at $
Where v is final velocity and $u$ is initial velocity.
Given, $ v=25\,m/s,\,u=5\,m/s $
$ \therefore 25=5+10\,\,t $
$ \Rightarrow t=\frac{20}{10}=2\,s $ ,