The strength of the fireman in vertical direction will be given by F = m * g. Then, the work done will be given by definition by W = F * d. Substituting the expression of the Force in that of the work, we have that the work will be W = m * g * d. Substituting the given values and assuming that g = 10m / s ^ 2, we have a total work of W = (73) * (10) * (9) = 6570 J
Kinetic energy is the energy for a catapult.
In order to balance the stick on the pivot, the total "moments" must be equal on both sides. A "moment" is (a weight) x (its distance from the center).
for the 5N weight: Moment = (5N) x (3 cm) = 15 N-cm
for the 12N weight: Moment = (12N) x (5 cm) = 60 N-cm
Sum of the moments trying to pull the stick down on that side = 75 N-cm
Whatever we hang on the other side has to provide a moment of 75 N-cm in the other direction. We have a 25N weight. Where should we hang it ?
(25N) x (distance from the pivot) = 75 N-cm
Distance from the pivot = (75 N-cm) / (25 N)
<em>Distance from the pivot = 3 cm </em>
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