Circular Motion

[greatwhiteshark]

I have two questions. I can't find any formula in my book to help me,
and I don't know where to begin.

1) An electric hoist is being used to lift a piece of equipment. The
diameter of the drum on the hoist is 10 inches, and the equipment must
be raised 1 foot. Find the number of degrees through which the drum
must rotate.

2) A car is moving at a rate of 50 miles per hour and the radius of
its wheels is 2.5 feet. A) find the number of revolutions per minute
the wheels are rotating. B) Find the angular speed of the wheels in
radians per minute.

What formulas do I use? Also, what values do I plug and where in the formulas do I plug the given data? I can take it from there.

 

[Gene]

1) The distance the rim of the drum moves is r*theta. Get the units the same and change theta radians to degrees.

2) 50 mi/hr*5280 ft/mi * 60 min/hr = ft/min
The wheel moves pi*d ft/rev
1 rev = 360° = 2 pi radians.

 

[greatwhiteshark]

ok

Good job.