Question

The atlas stone’s is a strong man competition where athletes have to load 5 stones of masses 100kg, 120kg, 140kg, 160kg and 180kg loaded onto 5 platforms, each at a height of 125cm. Travis Ortmayer from the USA, who completed all 5-atlas stones in 15.83s, and used to hold the world record for this event.
How much mechanical work in Joules does Travis do in lifting all 5 stones? Use g=10 m/s2 No partial credit will be given if there is no work shown. Do not include units in your answer.

Answer 1

Answer: 6250 joules

Explanation:

The work needed to lift an object of mass M by a height H is equal to:

w = M*g*H

where h = 10m/s^2

then the total work that he did is equal to the sum of the work for every stone:

W = (100kg*g*H) + (120kg*g*H) + (140kg*g*H) + (160kg*g*H) + (180kg*g*H)

 = (100kg + 120kg + 140kg + 160kg + 180kg)*g*H

= (500kg)*g*H

and now we can repalce g by 10m/s^2 and H by 125cm

But you can notice that we have two different units of distance, so knowing that 100cm = 1m

we can write H =  125cm = (125/100) m = 1.25 m

Then we have:

H = 500kg*10m/s^2*1.25m = 6250 J