Question

A boy starts moving along circular path of radius 7m
if the boy moves uniformly with 4 m/s then average
velocity after half revolution.​

Answer 1

Given:

A boy starts moving along circular path of radius 7m. The boy moves uniformly with 4 m/s.

To find:

Average velocity after half revolution.

Calculation:

Let time take for half revolution be t

$\therefore \: t = \dfrac{ \frac{1}{2} \times 2\pi r }{speed}$

$= > \: t = \dfrac{ \pi r }{speed}$

$= > \: t = \dfrac{ \frac{22}{7} \times 7}{4}$

$= > \: t = \dfrac{ 22}{4}$

$= > t = 5.5 \: sec$

Displacement for half revolution will be equal to the diameter of the circular track.

$\therefore \: displacement = 2r = 14 \: m$

Average velocity:

$\therefore \: avg. \: v = \dfrac{displacement}{time}$

$= > \: avg. \: v = \dfrac{14}{5.5}$

$= > \: avg. \: v = 2.54 \: m {s}^{ - 1}$

So , final answer is :

$\boxed{ \sf{ \large{ \: avg. \: v = 2.54 \: m {s}^{ - 1} }}}$

Answer 2

Answer:

A boy starts moving along circular path of radius 7m. The boy moves uniformly with 4 m/s.

To find:

Average velocity after half revolution.

Calculation:

Let time take for half revolution be t

\therefore \: t = \dfrac{ \frac{1}{2} \times 2\pi r }{speed}∴t=speed21×2πr

= > \: t = \dfrac{ \pi r }{speed}=>t=speedπr

= > \: t = \dfrac{ \frac{22}{7} \times 7}{4}=>t=4722×7

= > \: t = \dfrac{ 22}{4}=>t=422

= > t = 5.5 \: sec=>t=5.5sec

Displacement for half revolution will be equal to the diameter of the circular track.

\therefore \: displacement = 2r = 14 \: m∴displacement=2r=14m

Average velocity:

\therefore \: avg. \: v = \dfrac{displacement}{time}∴avg.v=timedisplacement

= > \: avg. \: v = \dfrac{14}{5.5}=>avg.v=5.514

= > \: avg. \: v = 2.54 \: m {s}^{ - 1}=>avg.v=2.54ms−1

So , final answer is :

\boxed{ \sf{ \large{ \: avg. \: v = 2.54 \: m {s}^{ - 1} }}}avg.v=2.54ms−1