A particle has initial velocity ( 2 i + 3 j ) and acceleration ( … - Vidyadip

MCQ

A particle has initial velocity $\left( {2\hat i + 3\hat j} \right)$ and acceleration $\left( {0.3\hat i + 0.2\hat j} \right)$. The magnitude of velocity after $10\, seconds$ will be

A
$5\, units$
B
$9\, units$
C
$9\sqrt 2 \,unit$
✓
$5\sqrt 2 \,unit$

✓

Answer

Correct option: D.

$5\sqrt 2 \,unit$

d
$(\overrightarrow{\mathrm{v}})_{\mathrm{att}=10 \mathrm{sec}}=\overrightarrow{\mathrm{u}}+\overrightarrow{\mathrm{a}} \mathrm{t}=(2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}})+(0.3 \hat{\mathrm{i}}+0.2 \hat{\mathrm{j}}) \times 10$

$=5 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}$

$\therefore$ Magnitude $=\sqrt{5^{2}+5^{2}}=5 \sqrt{2} \mathrm{units}$

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