Question

A particle has initial velocity $4\hat{i}m/s$ and a uniform acceleration of $1.5\hat{j}\text{m/}{\text{s}}^2$ . Its speed after 2 sec will be

• A. $7m/s$
• B. $1m/s$
• C. $5m/s$
• D. $6m/s$

Answer 1

The correct option is C $5m/s$

$\overrightarrow{u}=4\overrightarrow{i},\overrightarrow{a}=1.5\overrightarrow{j},t=2s$

using : $\overrightarrow{v}=\overrightarrow{u}+\overrightarrow{a}t$

$\overrightarrow{v}=4\overrightarrow{i}+1.5\overrightarrow{j}\times 2$

$\overrightarrow{v}=4\overrightarrow{i}+3\overrightarrow{j}$

$\mid \overrightarrow{v}\mid =5m/s$