Q

# Tell me? - Kinematics - NEET

A particle has initial velocity $(3\hat{i}+4\hat{j})$ and has acceleration $(0.4\hat{i}+0.3\hat{j})$. It's speed after 10 s is:

• Option 1)

7 units

• Option 2)

$7\sqrt{2}\: units$

• Option 3)

8.5 units

• Option 4)

10 units

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As learnt in

1st equation or velocity time equation -

$V=u+at$

V = Final velocity

u = Initial velocity

A = acceleration

T = time

-

$\vec{v} = \vec{u}+\vec{a}t$

$\vec{v} = \left ( 3\hat{i}+4\vec{j} \right )+\left ( 0.4\hat{i}+0.3\hat{j} \right )\times 10$

$\vec{v} = 3\hat{i}+4\hat{j} + 4\hat{i}+3\hat{j}$

$\vec{v} = 7\hat{i}+7\hat{j}$

$\left | v \right |= \sqrt{49+49}= 7\sqrt{2}$

Option 1)

7 units

This option is incorrect

Option 2)

$7\sqrt{2}\: units$

This option is correct

Option 3)

8.5 units

This option is incorrect

Option 4)

10 units

This option is incorrect

As learnt in

1st equation or velocity time equation -

$V=u+at$

V = Final velocity

u = Initial velocity

A = acceleration

T = time

-

$\vec{v} = \vec{u}+\vec{a}t$

$\vec{v} = \left ( 3\hat{i}+4\vec{j} \right )+\left ( 0.4\hat{i}+0.3\hat{j} \right )\times 10$

$\vec{v} = 3\hat{i}+4\hat{j} + 4\hat{i}+3\hat{j}$

$\vec{v} = 7\hat{i}+7\hat{j}$

$\left | v \right |= \sqrt{49+49}= 7\sqrt{2}$

Option 1)

7 units

This option is incorrect

Option 2)

$7\sqrt{2}\: units$

This option is correct

Option 3)

8.5 units

This option is incorrect

Option 4)

10 units

This option is incorrect

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