- Home
- Standard 9
- Science
7. MOTION
medium
Joseph jogs from one end $A$ to the other end $B$ of a straight $300\, m$ road in $2\, min$ $30\, sec$ and then turns around and jogs $100 \,m$ back to point $C$ in another $1\, min$. What are Joseph's average speeds and velocities in jogging from $A$ to $B$ ?
A
$0.2 \,m s ^{-1}$ and $2.0 \,m s ^{-1}$
B
$2 \,m s ^{-1}$ and $2 \,m s ^{-1}$
C
$4 \,m s ^{-1}$ and $2 \,m s ^{-1}$
D
$2 \,m s ^{-1}$ and $4 \,m s ^{-1}$
Solution
Total Distance covered from $AB = 300\, m$
Total time taken $= 2 \times 60 + 30 \,s =150\, s$
Therefore, Average Speed from $AB$ = Total Distance / Total Time
$=300 / 150 \,m s ^{-1}$
$=2 \,m s ^{-1}$
Therefore, Velocity from $A B=$ Displacement $A B /$ Time
$=300 / 150 m s ^{-1}$
$=2 \,m s ^{-1}$
Standard 9
Science
