Question

If a car has tires with a radius of 1.5 ft and the tires are spinning at 840 rpm (revolutions per

Answer 1

Answer:

89·98 mph

Step-by-step explanation:

First, we get the circumference of the tires:

Circumference = $\pi$ × (radius × 2)

Circumference = 3.142 × (1·5 × 2)

Circumference = 3·142 × 3

Circumference = 9·426 ft

The circumference of the tire is equal to one round.

      1 round = 9·426 ft

840 rounds = ?

We cross multiply to get the length that the tires would cover in a minute

= 840 × 9·426

       1

    1 minute = 7917·84 ft

60 minutes = ?

60 × 7917·84

          1

= 475070·4 ft

      5280 feet = 1 mile

475070·4 feet = ?

475070·4 × 1

     5280

475070·4 ÷ 5280 = speed of the car in mph

89·97545

Round this off to 2 decimal places...

= 89·98 mph

hope this helps! =)