- #36
NateTG
Science Advisor
Homework Helper
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Ok let's take a look at this a different way. Consider that the mechanical advantage that the pulley provides is proportional to the rates of movement of the rope and the load.
Now if the person pulls a meter of rope through the pulley, the platform must rise by a meter, since the distance from the person to the pulley is fixed. Therefore the mechanical advantage is 1, and the person must pull the full weight of the platform and the person.
For the formally inclined, consider that the amount of work the person does is the force that he needs to move the rope multiplied by the distance that he moves it, and you will find the same result.
Since most people can dead lift more than their body weight, the answer to the original question depends on the weight and geometry of the platform/pulley arrangement.
Now if the person pulls a meter of rope through the pulley, the platform must rise by a meter, since the distance from the person to the pulley is fixed. Therefore the mechanical advantage is 1, and the person must pull the full weight of the platform and the person.
For the formally inclined, consider that the amount of work the person does is the force that he needs to move the rope multiplied by the distance that he moves it, and you will find the same result.
Since most people can dead lift more than their body weight, the answer to the original question depends on the weight and geometry of the platform/pulley arrangement.