Answer:
The work done by Isaac can be calculated using the formula:
work = force x distance
where force is the amount of force applied and distance is the distance over which the force is applied. In this case, the force applied by Isaac is 42 Newtons and the distance over which the force is applied is 6 meters. However, we need to calculate the actual distance moved by the box, which is different from the distance over which the force is applied.
To calculate the distance moved by the box, we can use the formula for the mechanical advantage of a lever:
mechanical advantage = distance moved by effort / distance moved by load
In this case, the effort is the force applied by Isaac, the load is the weight of the box (15 kg), and the mechanical advantage is the ratio of the distances moved. We can rearrange this formula to solve for the distance moved by the load:
distance moved by load = distance moved by effort / mechanical advantage
In this case, the distance moved by effort is 2 meters (the height the box is lifted), and the mechanical advantage can be calculated using the ratio of the lengths of the lever arms (assuming the lever is a simple machine). Let's say the lever has two arms, one on each side of the pivot point, with lengths of L1 and L2. The mechanical advantage of the lever is:
mechanical advantage = L2 / L1
Assuming Isaac applied the force at the end of one arm, and lifted the load at the end of the other arm, we can say that the ratio of the lengths of the arms is:
L2 / L1 = 2 / 6
Simplifying, we get:
L2 = L1 / 3
This means that the load is lifted a distance of 2/3 meters (or 0.67 meters), which is the distance moved by the load. Now we can calculate the work done by Isaac:
work = force x distance
= 42 N x 6 m
= 252 J
Therefore, the amount of work done by Isaac to lift the 15-kilogram box is 252 Joules. The correct answer is (B) 252 Joules.