Here is another hydrostatic force problem, I hope this isn't double posting. It's not an identical thread, so it shoudn't be right? Well here it is:

A tank is 7 m long, 5 m wide, 3 m high, and contains kerosene with density 820 kg/m3 to a depth of 2.5 m. (Give your answers correct to three significant figures.)

It first asks to give the hydrostatic pressure at the bottom of the tank. Isn't that just 820*9.8*2.5?? Thats what I thought, so I put down for my answer 2.01*10^4 is that 3 sig figs? but it was wrong.

Then, it asks for the hydrostatic force at the bottom of the tank.

I think you pull out the 820*9.8 and you have the integral from 0 to 2.5 of (x* some area, I don't know how to find that)

Finally, it asks for the hydrostatic force on one end of the tank, which I'm not sure about. Whats the difference between this question and the previous one?

Thanks!