Question

An athlete moves on a circular track of radius 7 m and completes one round in 60 seconds.
Find distance and displacement after 135 seconds.

Answer 1

Answer:

15.7m answer

Explanation:

15.7m

1m=60 second

2m=120 second

1m=7m.

2m=2×7=14.

15 second is left.

60÷15=4.

7÷4=1.7

14+1.7=15.7.ans.

Answer 2

Answer:

Distance = 98.96 m = 99 m ; displacement =

Explanation:

Distance :

Radius = r = 7 m

As one round is covered in 60 s so, the rounds covered in 135 s are:

$\frac{135}{60}$ = 2.25 rounds

So,  distance covered in one round = Circumference of circle

= 2πr

= 44 m

Distance covered in 2.25 rounds = 44 × 2.25

= 99 m

So, Total distance covered in 135 seconds = 99 m

Displacement :

distance covered in one round = 44 m

distance covered in 0.25 rounds = 44 × 0.25

= 11 m

Distance covered in 0.25 rounds with respect to diameter of circle = 11 ÷ 3.14

= 3.5 m

so, displacement = 3.5 m