Question

1.In a race athlete takes 3 rounds of a circular track of length 200m in 2 hrs 45 minutes.(i) Calculate the ratio of displacement and distance covered.(ii) Is the motion uniform or non-uniform. (iii) Calculate average speed and average velocity.​

Answer 1

Given:

In a race athlete takes 3 rounds of a circular track of length 200m in 2 hrs 45 minutes.

To find:

• The ratio of displacement and distance covered.
• Is the motion uniform or non-uniform.
• Calculate average speed and average velocity.

Calculation:

1st part :

The athlete completed three rounds of the circular track in the specified time and hence his starting point and stopping point are same. As a result, his Displacement is Zero

Distance = 3 × 200 = 600 m

$\boxed{ \sf{ \dfrac{displacement}{distance} = \dfrac{0}{600} = 0}}$

2nd part:

The motion is Uniform Circular Motion because the athlete moves with constant speed.

3rd part:

$\boxed{ \sf{avg. \: speed = \dfrac{600}{120 + 45} = 3.63 \: m \: {min}^{ - 1} }}$

$\boxed{ \sf{avg. \: velocity = \dfrac{0}{120 + 45} = 0 \: m \: {min}^{ - 1} }}$