A truck starting from rest moves with an acceleration of 5,m / s ^2 for 1 sec and then moves with co

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4-1.Newton's Laws of Motion

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A truck starting from rest moves with an acceleration of $5\,m / s ^2$ for $1 sec$ and then moves with constant velocity. The velocity w.r.t. ground v/s time graph for block in truck is (Assume that block does not fall off the truck)

A

B

C

D

None of these

Solution

For $t < 1\,sec$

$\therefore a_B=2\,m / s ^2$

and velocity of truck is $5\,m / s$

$\therefore$ Friction will act after $1\,sec$ due to relative motion between block and truck

$5=2 \times t$

$t=2.5\,sec .$

Standard 11

Physics

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