Question

A runner runs on a circular track of radius 35 m. Running uniformity, if he covers one round ofthis distance in 21 seconds, what is his Average velocity after completing two rounds of the track? How much time does he takes to run 100 m? (Take pie=22/7)

Answer 1

$\blue{\bold{\underline{\underline{Answer:}}}}$

$\green{\tt{\therefore{Avg.\:speed\approx10.5\:m/s}}}$

$\green{\tt{\therefore{Time\:to\:cover\:100\:m\approx9.5\:sec}}}$

$\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

$\green {\underline{\underline \bold{Given : }}} \\ \tt: \implies Radius \: of \: circular \: track = 35 \: m \\ \\ \tt: \implies Time \: taken \: to \: cover \: one \: round = 21 \: second \\ \\ \red{\underline{\underline \bold{To \: Find: }}}\\ \tt: \implies Avg. \: velocity \: after \: completing \: two \: round = ? \\ \\ \tt: \implies Time \: taken \:to \: cover \: 100 \: m \: distance = ?$

• According to given question :

$\bold{As \: we \: know \: that} \\ \tt: \implies Distance \: of \: track = 2\pi r \\ \\ \tt: \implies Distance \: of \: track =2 \times \frac{22}{7} \times 35 \\ \\ \tt: \implies Distance \: of \: track =2 \times 22 \times 5 \\ \\ \tt: \implies Distance \: of \: track =220 \: m \\ \\ \bold{As \: we \: know \: that} \\ \tt: \implies Speed = \frac{Distance}{Time} \\ \\ \tt: \implies Speed = \frac{220}{21} \: m/s \\ \\ \bold{Qs \: we \: know \: that} \\ \tt: \implies Avg.\: speed = \frac{ \frac{220}{21} + \frac{220}{21} }{2} \\ \\ \tt: \implies Avg.\: speed = \frac{440}{42} \\ \\ \green{\tt: \implies Avg.\: speed \approx10.5 \: m/s} \\ \\ \bold{For \: time \: to \: travel \: 100 \: m} \\ \tt: \implies Time = \frac{Distance}{Speed} \\ \\ \tt: \implies Time = \frac{100}{10.5} \\ \\ \green{\tt: \implies Time \approx9.5 \: sec}$

Answer 2

$</p><p>\tt{\huge{\pink{Hello!!! }}}$

$</p><p>\tt{\purple{\boxed{\boxed{\bullet{Question \: - }}}}}$

A runner runs on a circular track of radius 35 m.

Running uniformity, if he covers one round of this distance in 21 seconds, what is his Average velocity after completing two rounds of the track?

How much time does he takes to run 100 m?

Take pi = 22/7.

$</p><p>\tt{\blue{-------------}}$

$</p><p>\tt{\green{\boxed{\boxed{\bullet{Solution \: - }}}}}$

$\tt{ \red{From \: the \: question \: we \:can \: gather \: that \: : }} \: \\ \\ \tt{ \purple{ \bullet{ \boxed{Displacement \: = 0 \: m. }}}} \\ \\ \tt{ \green{ \bullet{t \: = \: 42 \: sec.}}}$

The body covers two rounds of the track and returns to it's Innitial position. Hence, the displacement is zero.

Distance travelled by the body is Circumference = 2πr = 220 m.

Hence :

Average Speed = Total Distance Travelled / Total Time Taken =>

$\tt { \blue{Average \:Velocity \: = 0 }} \\ \\ \tt{ \orange{Average \: Speed \: \approx \: 10.5 \: m.s}}$

$</p><p>\tt{\red{ \therefore{Time \: = \: \dfrac{Distance}{Speed} \approx 9.5 \: sec }}}$

$</p><p>\tt{\blue{-------------}}$