I want to lift a 3000kg car with a hydraulic jack. With a lever, I can easily build up by hand a force = 300 N on a piston of 10cm^2 surface area. What area should the piston have that pushes the car?

Question

I want to lift a 3000kg car with a hydraulic jack. With a lever, I can easily build up by hand a force = 300 N on a piston of 10cm^2 surface area. What area should the piston have that pushes the car?
a. 1 cm^2; b. 10 cm^2; c. 100 cm^2; d. 1000cm^2
I answered with c. 100 cm^2 which is incorrect. Thank you for your help.

Steve · Answer

3000kg weighs 3000*9.8 = 30000N So, the weight ratio is 100, not 10. So, you need 100*10 = 1000 cm^2 of area to push it.