Define Circular Motion

(i) Define circular motion. (ii) What is the difference between uniform motion in a straight line and … at the end of 2 min and 20…

Answers:

(i) The motion of the body moving  around a fixed point in a circular path.

(ii) Uniform motion in straight line 

(a) The direction of motion of object does not change. 

(b) If an object moves with a constant speed its accelera-tion is zero. 

Uniform in circular motion  

(a) Direction changes continuously. 

(b) Acceleration is  not zero even  on moving with constant speed. 

(iii) Diameter of track = 200 m

Radius = 100 m

The distance covered in 

40 sec = 2πr 

= 2π × 100 = 200π  

The distance covered in 2 min 20 sec (140sec) 

= 200 / 40 π × 140 = 700 π m

So, displacement will be 200 m

No. of complete rounds covered by athlele  

700 π / 200  π = 

He covers rounds.