How do i solve this problem?

Question

How do you solve this problem?

Thanks in advance for any help


The radius of each wheel of a car is 15 inches. if the wheels are turning at the rate of 3 rev/s how fast is the car moving. Express the answer in inches per second and miles per hour.

Answer 1

PART 1:

The wheel is 15 inches.

The circumference is:
2πr
= 2 π (15)
= 30 π
≈ 94.25 inches

But it makes 3 revolutions in a second, so that is:
3 x 94.25 ≈ 282.75 inches / second.

PART 2:

Now to express that in miles per hour.

If you go 282.75 inches in a second, you will go 60 times that in a minute, or 3600 times that in an hour.

282.75 x 60 x 60 = 1,017,876 inches / hour

But we want this in miles:

5280 feet x 12 inches/ft = 63,360 inches in a mile.

Now just divide:
1,017,876 / 63,360 ≈ 16.064 mph

Answer 2

First off you have to get the circumference:

d x pie = c
30 x 3.14 = 94.2 (we will use 94)

Then we find inches per second:

94 x 3 = 282

282 inches per second

Last we need the get the miles per hour:

1 mile = 63 360 inches
1 hour = 3 600 seconds

1 inches per second = 0.0568181818 miles per hour

282 x 0.0568181818 = 16.0227272676

So you en up with:

16mph & 282 inches per sec

Answer 3

Think it through:

From the radius determine the circumference. You now know how far each revolution goes.

Turn that in to a speed, because you're doing that distance 3 times each second.

Turn the raw value (inches per second) in to the desired units.

Answer 4

So the radius is 15 in. Then the circumference is 2Pi15, which is 30Pi, or about 94.25 in. Now, since 3rpm, that makes the rate of movement 282.75 in/sec. To convert

(282.75 in./sec) x (1 ft/12in) x (1 mile/ 5280 ft) x (60sec/ 1min) x (60 min/ 1 hr) = 16.07 mph

Answer 5

3 * (15 * 2) * pi = 282.6 in/sec
=282.6 in/sec * 1mile/63360in * 3600sec/1hr = 16.06 miles/hr