Question

a body completes one circumference of a circle of radius R in time T with average speed i​

Answer 1

Answer:

hi here is urr answer

Explanation:

radius is double of diameter.

it means circle×(2 times the radius)+time(T)

upon ave. speed

Answer 2

Answer:

Required distance: π*R/2 units

Required displacement: √2*R units

Explanation:

Hint: Displacement is the shortest distance travelled by the body from initial position to final position.

Given a body completes one round of a circle of radius R in 20 seconds.

Let A is the point where the body has started its motion. After 20 seconds the body returns to point A and again after 40 seconds the body returns at point A.

In 5 seconds, the body will complete a quarter of a circle.

So, the body will be at point B after 45 seconds.

Displacement Calculation

To calculate the displacement that is AB, let us apply Pythagoras theorem

Here OA=R and OB=R

So from Pythagoras theorem:

$Hypotenuse^2 =Side^2 +Side^2$

$AB^2 =OA^2 +OB^2$

$AB^2 =R^2 +R^2$

$AB=\sqrt{R^2+R^2$

= $\sqrt{2R^2 }$

$AB=\sqrt{2R}$

Given a quarter circle OAB. Take O(0,0), A(r,0) and B(0,r)

Distance is length of arc AB

=(1/4)(2πr) =(1/2)πr

Displacement is magnitude of AB vector=r√(2)