If a car covers 2/5^{th} of total distance with v₁ speed and 3/5^{th} distance with v₂ then aver

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2.Motion in Straight Line

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If a car covers $2/5^{th}$ of the total distance with $v_1$ speed and $3/5^{th}$ distance with $v_2 $ then average speed is

A

$\frac{1}{2}\sqrt {{v_1}{v_2}} $

B

$\frac{{{v_1} + {v_2}}}{2}$

C

$\frac{{2{v_1}{v_2}}}{{{v_1} + {v_2}}}$

D

$\frac{{5{v_1}{v_2}}}{{3{v_1} + 2{v_2}}}$

Solution

(d) Average speed $ = \frac{{{\rm{Total\, distance\, travelled}}}}{{{\rm{Total \,time\, taken }}}}$

$ = \frac{x}{{\frac{{2x/5}}{{{v_1}}} + \frac{{3x/5}}{{{v_2}}}}}$ $ = \frac{{5{v_1}{v_2}}}{{3{v_1} + 2{v_2}}}$

Standard 11

Physics

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