A crane does 62500 joules of work to lift a boulder a distance of 25 meters. How much did the boulder weigh?

Answer 1

We know that 62500 joules of work was done against gravity of a distance of 25 meters. We need find the force that the crane applied to the boulder.

We know that work is equal to the force times the displacement so:

W=FΔd

62500=F(25) <-Now divide both sides by 25 to isolate "f"

2500=F

We now know that the crane applied a force of 2500 Newtons to move the boulder. We know that this was done in the opposite force of gravity which means that we can use the formula for acceleration due to gravity to find the mass:

Fg=gm <- where Fg is the force due to gravity, g is the acceleration due to gravity and m is the mass of the object.

2500=9.81m <- divide both sides by one to find the mass

254.84=m <- this is the mass in kilograms of the boulder

260 kg would be the correct answer due to the lack of significant figures in the distance measurement .