Trigonometry-Velocity Question?

Question

HELP!! I'm having trouble figuring out this trig problem...thanks so much

The radius of each wheel of a car is 15 inches. If the wheels are turning at the rate of 3 revolutions per second, how fast is the car moving? Expess your answer in inches and in miles per hour

Answer 1

you need to find the circumference of the circle.

you know it goes around 3 times each second.

so multiply the cricumference by 3 to get the amount of distance the wheel roll through per second..

right now you have it in  inches per second..

convert your answer to miles per hour

good luck

Answer 2

The radius of each wheel of a car is 15 inches. If the wheels are turning at the rate of 3 revolutions per second, how fast is the car moving? Expess your answer in inches and in miles per hour

Penelope  Hi !!

Convertion

1mile = 63360 in

1hr = 60 min

1 min = 60 sec

Given

Radius = R = 15 in = 2.3674 x 10^-4 mile

Turn = 3 rev /sec = 10,800 rev /hr

Circunference of the wheel = Distance traveled per rev

Circuference of the wheel = 2πR

Circuference of the wheel = 2π(0.00023674)

Circuference of the wheel = 1.4867 x 10^-3

Circuference of the wheel = 0.0014867 mile/rev

Speed of the car = Distance traveled per rev x Circunference of the wheel

Speed of the car = 0.0014867 x 10,800

======================================...

Ans::Speed of the car = 16.06 miles/hr

======================================...

hope this helps

Answer 3

You can use dimensional analysis,

(3 rev/sec)(2pi*15 in/rev)(3600 sec/hr) = 324,000pi in/hr

Can you convert it to miles/hr?

Hint: Add two more chains (1 ft/12 in)(1 mi/1580 ft)

Answer 4

The car is moving at 1,017,876.02 inches per hour

and translated into miles, that is..

16.065 miles per hour.  (roughly. look at the bottom for the exact answer)

You do this by first finding out the circumference of a circle. You do that by the equation - 2*(pi)*r

R stands for radius and if you don't have a pi key on your calculator, it is roughly 3.14 (3.14159).

The equation for this problem is 2*pi*15

The answer turns out to be 94.24777961.

Then you triple that to get the amount of inches the car travels in a second.

94.24777961*3=282.7433388

Meaning that the car travels at roughly 282.75 inches per second.

That also is 23.56 feet, and 7.85 yards.

Then, to get the amount of inches the car travels in a minute, you do 282.7433388*60, because there are 60 seconds in a minute.

This turns out to be 16,964.60033 inches per minute (a.k.a. - 1413.716694 feet per minute, and 47.07223139 yards per minute.

Then, to find the amount of inches the car travels in an HOUR, you do  16,964.60033*60 (because there are 60 minutes in an hour) and this turns out as...

1,017,876.02 inches per hour   a.k.a. ...

84,823.00165 feet per hour

28,274.33389 yards per hour

and...

to get the amount in miles per hour, you take the amount that you got for feet per hour, and divide it by 5,280 because there are 5,280 feet in one mile.

So 84,823.00165/5280 is....

16.06496243 miles per hour.

Answer 5

v=wr

v=(3/sec)(2pi15)(15in)

v=4241in/sec

4241in/sec(1/12ft/in)(1/5280mi/ft)

(3600sec/hr)=240.97mi/hr

ANSWER