An athlete is running on a circular track. He runs a distance of 450 m in 30 s before returning to his original position. What is his average speed and velocity? *
Answers
Explanation:
ANSWER
The diameter of the circular track is given as 200 m. That is, 2r=200 m.
From this radius is calculated as Radius, r = 100 m.
In 40 sec the athlete complete one round. So, in 2 mins and 20 secs, that is, 140 sec the athlete will complete = 140 / 40 = 3.5 (three and a half) rounds.
One round is considered as the circumference of the circular track.
The distance covered in 140 sec = 2πr×3.5=2×3.14×100×3.5=2200 m.
For each complete round the displacement is zero. Therefore for 3 complete rounds, the displacement will be zero.
At the end of his motion, the athlete will be in the diametrically opposite position. That is, displacement = diameter = 200 m.
Hence, the distance covered is 2200 m and the displacement is 200 m.
Answer:
Solution:
Given: Total distance travelled = 40,
Total displacement = 0, as he returns to his original position.
Total time = 25 s.
To find: i. Average speed.
ii. Average velocity.
Formulae: i. Average speed = Total distance covered/Total time taken.
ii. Total displacement/Total time taken.
Calculation: From formula (i),
Average speed = 400/25 = 16 m/s.
From formula (ii),
Average velocity = 0/25 = 0 m/s.
Ans:- i. Average speed of athlete is 16 m/s. ii. As the athlete returns to his original position, his average velocity is zero.