Question

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

• A. $3\text{ }m{{s}^{-1}}$ in north direction
• B. $3\text{ }m{{s}^{-2}}$ in north direction
• C. $\text{15 }m{{s}^{-2}}$ in north direction
• D. $\text{3 }m{{s}^{-2}}$ in south direction

Answer 1

Answer: (B)

$3\text{ }m{{s}^{-2}}$ in north direction

Answer 2

The correct option is(B): $3\text{ }m{{s}^{-2}}$in north direction.

$a=\frac{v-u}{t}=\frac{25-10}{5}$ $=\frac{15}{5}=3\,m/{{s}^{2}}$ in north direction.