Pulley Vs No Pulley
To demonstrate mechanical advantage with a block and tackle.
Two double sheave pulleys, four lead bricks in bucket, rope, cable to ceiling mount. Use rolling crane from Machine Shop in small classrooms.
Do not release the rope and allow the bucket of lead bricks to fall on your feet.
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 order to raise the bucket one foot.