Linear & Angular Speed...2

[nycmathguy]

Section 4.1

Seeking the set up only for parts (a) & (b).

 

[MathLover1]

A computerized spin balance machine rotates a 25-inch-diameter tire at 480 revolutions per minute.

(a) Find the road speed (in miles per hour) at which the tire is being balanced. (Round your answer to two decimal places.)


speed s=25*pi *480 (in/min)*(1ft/12in)*(1mi/5280ft)*60(min/hr) ...cancel in, ft, min, and you got mil/h
s=37699.11184307752(1/12)(1/5280)*60(mil/h)
s=(35.69991651806583)(mil/h)
s= 35.70 (mil/h)


(b) At what rate should the spin balance machine be set so that the tire is being tested for 45 miles per hour? (Round your answer to two decimal places.)


480 (rev/min)/35.7(mi/hr) = x/45(mil/h)
x=(480 (rev/min)*45(mil/h))/35.7(mi/hr) ...simplify
x=(480 (rev/min)*45/35.7
x = 605.06 (rev/min)

 

[nycmathguy]

A computerized spin balance machine rotates a 25-inch-diameter tire at 480 revolutions per minute.

(a) Find the road speed (in miles per hour) at which the tire is being balanced. (Round your answer to two decimal places.)


speed s=25*pi *480 (in/min)*(1ft/12in)*(1mi/5280ft)*60(min/hr) ...cancel in, ft, min, and you got mil/h
s=37699.11184307752(1/12)(1/5280)*60(mil/h)
s=(35.69991651806583)(mil/h)
s= 35.70 (mil/h)


(b) At what rate should the spin balance machine be set so that the tire is being tested for 45 miles per hour? (Round your answer to two decimal places.)


480 (rev/min)/35.7(mi/hr) = x/45(mil/h)
x=(480 (rev/min)*45(mil/h))/35.7(mi/hr) ...simplify
x=(480 (rev/min)*45/35.7
x = 605.06 (rev/min)

This problem requires unit conversion. I am terrible when it comes to unit conversion. This requires more practice at my end, not to mention that word problems in general has been a weakness for me since middle school and that's a long time.

How about this link?

Converting to Decimal Degree Form

 

[MathLover1]

that is physics, a lot of unit conversion is required

 

[nycmathguy]

that is physics, a lot of unit conversion is required

I must stay away from physics. In fact, I will post lots of unit conversion problems in the coming days (maybe this weekend). This concept is now taught as early as middle school. I don't recall ever learning unit conversion back in 1977, 1978 and 1979.