A scooter starts from rest moves in a straight line with a constant acceleration and covers a distan

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7. MOTION

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A scooter starts from rest moves in a straight line with a constant acceleration and covers a distance of $64 \,m$ in $4 \,s$

$(i)$ Calculate its acceleration and its final velocity.

$(ii)$ At what time the scooter had covered half the total distance ?

Option A

Option B

Option C

Option D

Solution

$(i)$ $a=? ; u=0 ; S =64 m ; t=4 s$

Using the equation $S=u t+1 / 2 a t^{2},$ we have

$64=0+a(4)^{2}$

or $a=4 m s ^{-2}$

Using the equation $v=u+\mu t,$ we have

$v=0+4 \times 4=16 m s ^{-1}$

$(ii)$ Given $S=32 m , t=?, d=4 m s ^{-2}$

Using the equation $S=u t+\frac{1}{2} a t^{2}$

$32=0^{\prime}+4 \times(t)^{2}$ or $t=2.82 s$

Standard 9

Science

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