PURPOSE: To demonstrate mechanical advantage with a block and tackle.
DESCRIPTION: Try to lift the bucket filled with lead bricks. Hook the bucket onto the lower pulley and use this block and tackle arrangement to raise the load. The mechanical advantage is about 4:1, so that one must draw four feet of rope in o rder to raise the bucket one foot.
SUGGESTIONS: Do not release the rope and allow the bucket of lead bricks to fall on your feet.
REFERENCES: (PIRA 1M20.20)
EQUIPMENT: Two double sheave pulleys, four lead bricks in bucket, rope, cable to ceiling mount. Use rolling crane from Machine Shop in small classrooms.
SETUP TIME: 5 min.
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