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.