Each tire on a car has a radius of 15 inches. The tires are rotating at 350 revolutions per minute. Find the speed of the automobile to the nearest mile per hour.

Question

mathlegend · Answer

Formula I believe for this is...

t = r*theta

mathlegend · Answer

I definitely need some guidance on this one.

anonymous · Answer

I would do it as follows.
Determine circumference of the tire.  C= 2* pi * r.
Circumference * revolutions = inches per  minute
From there convert to miles per hour.

mathlegend · Answer

2*pi*15 = 94.2

Why do we need the circumference?

mathlegend · Answer

@nelsonjedi

richyw · Answer

one revolution would move the car forwards by a distance of one wheel circumference. assuming no slipping.

anonymous · Answer

With each revolution of the tire it will move forward 94.2 inches

mathlegend · Answer

Now i convert from inches to miles?

anonymous · Answer

and minutes to hours

mathlegend · Answer

94.2in/1min*1ft/12in*1mile/5280ft*60min/1hour=

Is my conversion setup correct?

mathlegend · Answer

I think I converted wrong...

anonymous · Answer

94.2 inches x 350 revolutions = inches traveled in one minute. 
inches traveled in one minute x 60 = inches traveled in one hour.
inches traveled in one hour / 12 in in foot / 5280 feet in file = mph