Initial velocity of a projectile is vec u = (4hat{i} + 3hat{j}),m/s it is moving with uniform accele

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3-2.Motion in Plane

easy

The initial velocity of a projectile is $\vec u = (4\hat i + 3\hat j)\,m/s$ it is moving with uniform acceleration $\vec a = (0.4\hat i + 0.3\hat j)\, m/s^2$ The magnitude of its velocity after $10\,s$ is.........$m/s$

A

$3$

B

$4$

C

$5$

D

$10$

Solution

$\overrightarrow{\mathrm{v}}=\overrightarrow{\mathrm{u}}+\overrightarrow{\mathrm{a}} \mathrm{t}$

$=(4 \hat{\imath}+3 \hat{\jmath})+(0.4 \hat{\imath}+0.3 \hat{\jmath}) \times 10$

$=8 \hat{\mathrm{i}}+6 \hat{\mathrm{j}}$

Its magnitude is

$|\overrightarrow{\mathrm{v}}|=\sqrt{(8)^{2}+(6)^{2}}=10 \mathrm{m} / \mathrm{s}$

Standard 11

Physics

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