Question

ET
An object covers (1) half a rotation (ii) one-fourth rotation in a
given time interval. Find the distance and displacement in each
case.​

Answer 1

Explanation:

The radius of the circle= r

(i) When it completes half circle:-

(Refer to Image 1)

Distance=

2

circumference

=

2

2πr

Distance= πr

Displacement= r+r=2r

(ii) When it completes 3/4

th

of the circle:-

The distance covered=

4

3

(circumference)

⇒

4

3

(2πr)=

2

3

πr

The displacement= AB (Refer to Image 2)

By using pythagoras theorem

AB

2

=r

2

+r

2

⇒AB

2

=2r

2

⇒AB=

2

r

Displacement=

2

r

Distance=

2

3

πr

solution