Question

(3) If a tire rotates at 400 revolutions per minute when the car is traveling 72km/h, what is the circumference of the tire?

Show all your steps.

Answer 1

3 meters.

Explanation:

400 rev / minute = 400 × 60 rev / 60 minutes

= 24,000 rev / hour

24,000 × C = 72,000 m : C is the circumference

C = 3 meters

Answer 2

3 meters

Explanation:

72 km / hour * 1 hour/ 60 min * 1000m/ 1 km

72000 meters /60 minute

1200 meters / minute

velocity = radius * w

Where w is 2*pi * the revolutions per minute

1200 = r * 2 * pi *400

1200 / 800 pi = r

1.5 /pi = r meters

We want to find the circumference

C = 2 * pi *r

C = 2* pi ( 1.5 / pi)

C = 3 meters