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?”

  1. acepimp2  on June 16th, 2013

    171.97 degree

    Reply

  2. Scott R  on June 16th, 2013

    so 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

    Reply

  3. Irv S  on June 16th, 2013

    12″ : 8 Pi” = x : 360
    do the arithmetic.

    Reply


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