Question

An athlete completes one round of a circular track of diameter 200m in 30 s.  Find 

(i) the distance travelled by the athlete and

(ii) the magnitude of the displacement of the athlete at the end of 30 s.

(iii)the speed and velocity of the athlete in 30s.​

Answer 1

Answer:

Distance = 628 m

Displacement = 0 m

Speed = 21 m/s

Velocity = 0 m/s

Explanation:

Diameter of track = 200 m

Radius of track = r = 100 m

Time taken = t = 30 s

1)

Distance travelled = one round of track = circumference of track = 2πr = 200π = 3.14 × 200 = 314 × 2 = 628 m

2)

Displacement = 0 m as initial and final point is the same

3)

Speed = Distance/ Time = 628/30 = 62.8/3 = 20.9333

Speed = 21 m/s [approx.]

Velocity = 0 m/s [as displacement = 0]