Question

An object travels north with a velocity of $10\,m{{s}^{-1}}$ and then speeds up to a velocity of $25\,m{{s}^{-1}}$ in 5 s. The acceleration of the object in these 5 s is:

• A. $12\,m{{s}^{-2}}$ in north direction
• B. $3\,m{{s}^{-2}}$ in north direction
• C. 15ms 2 in north direction
• D. $3\,m{{s}^{-2}}$ in south direction

Answer 1

The Correct Option is B

Rate of change of velocity is defined as acceleration. Acceleration
$a=\frac{\Delta v}{\Delta t}=\frac{{{v}_{2}}-{{v}_{1}}}{\Delta t}$
Given, ${{v}_{1}}=10\,m/s,\,{{v}_{2}}=25\,m{{s}^{-1}},\Delta t=5s$
$\therefore$ $a=\frac{25-10}{5}=3\,m{{s}^{-2}}$
in north direction.