Question

An athlete run
with uniform speed along a circular track of radius 42 metre complete one round in 40 seconds calculate average speed and average velocity in 10 ^ 0 to 10

Answer 1

Explanation:

Circumference of circle = 2¶r

= 2 x 22/7 x 42

= 84m

in 40s 84m was, covered

Then in1s distance covered=84/40= 2.1m

In 10s distance covered = 2.1x 20 = 21m

Total distance = 21 - 2.1 = 18.9m

Total time = 10 - 1 = 9s

Avg. Speed = 18.9/9 = 2.1m/s

In 10s it will quarter distance -

Draw fig

The displacement will be a cord joining radius forming a right ang. Triangle.

That cord =2{sq.rt}42

Avg.velocity = 2{sqr.rt} 42/9 = 1. 44m/s

Hope you understood well.