The mechanical advantage of the screw jack is calculated using the formula:
MA = (length of lever arm) / (pitch)
MA = 40cm / 2.0cm = 20
This means that for every turn of the screw, the load will be raised by a factor of 20.
Two practical applications of block and tackle pulley systems are:
1. Moving heavy loads: Block and tackle pulley systems are commonly used in construction and manufacturing industries to move heavy loads. The pulley system allows one person to lift or move a heavy object that would otherwise require multiple people to lift. The weight of the load is distributed among the pulleys, reducing the amount of force required to lift it.
2. Rigging sails on ships: Block and tackle pulley systems are used to rig the sails on sailboats and large ships. The pulleys provide a mechanical advantage, allowing the crew to adjust the tension on the sails with less effort. This is important for maintaining control of the ship and achieving maximum speed.
A screw jack with a lever arm of 40cm and a pitch 2.0cm is used to raise a heavy load. State two practical application of block and tackle pully system.
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