Question

If a body on a circular path of radius 21 cm with a velocity of 2 metre per second.find the time to complete half revolution

Answer 1

Correct Question

If a body is moving on a circular path of radius 21 cm with a velocity of 2 metre per second. Find the time taken by body to complete half revolution.

Given:

Radius of circular path, r= 21 cm

or, r= 21/100 m

Velocity of body, v= 2 m/s

To Find:

Time taken by body to complete half revolution

Solution:

We know that,

• $\pink{\boxed{\bf{Time=\frac{Distance}{Speed}}}}$

• Displacement is the shortest distance between starting and final position

• $\purple{\boxed{\bf{Circumference=2\pi\times Radius}}}$

$\rule{190}{1}$

Let the time taken by body to complete half revolution be t, C be the circumference of circular path and distance covered by by body after half revolution be D

So,

$\longrightarrow\rm{C=2\pi r}$

$\longrightarrow\rm{C=2\times\dfrac{22}{7}\times\dfrac{21}{100}}$

$\longrightarrow\rm{C=\dfrac{33}{25}\:m}$

It is clear that after half revolution final position of body is diametrically opposite to starting position

So,

$\longrightarrow\rm{D=\dfrac{C}{2}}$

$\longrightarrow\rm{D=\dfrac{\dfrac{33}{25}}{2}}$

$\longrightarrow\rm{D=\dfrac{33}{50}\:m}$

$\rule{190}{1}$

Also,

$\longrightarrow\rm{t=\dfrac{D}{v}}$

$\longrightarrow\rm{t=\dfrac{\dfrac{33}{50}}{2}}$

$\longrightarrow\rm{t=\dfrac{33}{100}}$

$\longrightarrow\rm\green{t=0.33\:s}$

Hence, the time taken by body to complete half revolution is 0.33 s.

Answer 2

Answer:

Explanation:

33