Answer:
6370 J
Step-by-step explanation:
By the law of energy conservation, the work done by the student would be the change in potential enegy from 1st floor to 3rd floor, or a change of 13 m
![W = E_p = mgh](https://img.qammunity.org/2021/formulas/physics/college/xdlqrxs2u08u668zw10p8wxc0tx2p5xujh.png)
where m = 50kg is the mass of the student, g = 9.8 m/s2 is the gravitational constant and h = 13 m is the height difference
![W = 50*9.8*13 = 6370 J](https://img.qammunity.org/2021/formulas/physics/college/a03c0ouqbj4cqffq7h04iy5lw0rc6mp1cl.png)