## Find the degrees a drum must rotate to lift a box 1 foot if the diameter of the pulley on the hoist is 8 inche?

An electric hoist is used to lift a box using a pulley. The diameter of the pulley is 8 in and the box must be raised 1 foot. find the number of degrees through which the drum must rotate to lift the item 1 foot.

### 3 Responses to “Find the degrees a drum must rotate to lift a box 1 foot if the diameter of the pulley on the hoist is 8 inche?”

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acepimp2on June 16th, 2013171.97 degree

Scott Ron June 16th, 2013so the correct way to do this is pretty simple. you use the equation:

s = r * theta

where

s = arc length (linear) ….. in this case one foot

r = radius of the pulley ( r = d/2 = (8in) / 2 = 4 in

theta = the angle you rotate through

solving for theta yields:

theta = s / r

= [1ft*(12in/1ft)] / (4 in)

theta = 3 radians

if you need your answer in degrees, simply multiply by (180/pi)

…… (360 degrees in 2pi radians)

theta = (3 radians) * (180degrees / pi radians)

theta = 171.9 degrees

Irv Son June 16th, 201312″ : 8 Pi” = x : 360

do the arithmetic.