Answer :
The person needs to add (gain) a weight of 146.4 kg in order to lift the rock using the lever.
The person needs to add (gain) a weight that is equal to the weight of the rock multiplied by the mechanical advantage of the lever.
To calculate the weight the person needs to add (gain), we can use the formula:
Weight added = Mechanical advantage × Weight of the rock
Weight added = 1.2 × 122 kg
Weight added = 146.4 kg
Therefore, the person needs to add (gain) a weight of 146.4 kg in order to lift the rock using the lever.
In summary, to determine the weight the person needs to add (gain) when using a lever to lift a rock, we multiply the weight of the rock by the mechanical advantage of the lever. In this case, the person needs to add a weight of 146.4 kg.
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