Question

A force of $6N$ acts on a body at rest and of mass $1kg$. During this time, the body attains a velocity of $30m/s$. The time for which the force acts on the body is

• A. 7 seconds
• B. 5 seconds
• C. 10 seconds
• D. 8 seconds

Answer 1

Answer: (B)

Force $(F)=6N$; Initial velocity $(u)=0$;
Mass $(m)=1kg$ and final velocity $(v)=30m/s$.
Therefore acceleration $(a)=\frac{F}{m}=\frac{6}{1}=6m/s^2$
and final velocity $(v)=30=u+at=0+6\times t$
or $t=5$ seconds.