Question

2. An object is moving with uniform speed in a circle of radius r. Calculate the
distance and displacement: (a) when it completes half the circle (b) when it
completes full circle.
2 Ma​

Answer 1

Answer:

a)Distance= πr

Displacement = 2r

b)Distance= 2πr

Displacement = 0

Explanation:

a) Distance= πr (as it completes half a circle 2πr/2 )

Displacement = 2r

b) Distance= 2πr

Displacement = 0 (it comes back to intial point )

Answer 2

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