Following graph describes motion of a girl going to meet her friend who stays 50, m from her house (

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7. MOTION

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The following graph describes the motion of a girl going to meet her friend who stays $50\, m$ from her house

$(i)$ How much time she takes to reach her friend's house ?

$(ii)$ What is the distance travelled by the girl during the time$-$interval $0$ to $12$ minute ?

$(iii)$ During which time-interval she is moving towards her house ?

$(iv)$ For how many minutes she was at rest, during the entire journey ?

$(v)$ Calculate the speed by which she returned home.

Option A

Option B

Option C

Option D

Solution

$(i)$ $14$ minute.

$(ii)$ $40 m +20 m =60 m$.

$(iii)$ Between $14$ to $16$ minutes.

$(iv)$ $2+2+2=6$ minutes.

$(v)$ Speed $=\frac{\text { Total distance covered }}{\text { Total time taken }}$

$=\frac{50 m }{2 min }=25 m \min ^{-1}$

$=\frac{25 \times 60}{1000} kmh ^{-1}=1.5 km h ^{-1}$

Standard 9

Science

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