Your question is Lever Force Calculation. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
If you have a set of pliers with the jaws 2" from the fulcrum and the lever 8" from the fulcrum, how much load do you have to apply to get 500 lbs of force on the jaws?