You are confusing "force" with "energy". When you move the jack handle down, say one foot while the car goes up 1/2 inch then, since "energy" is "distance times force", (1/2)F= (12)f so that f= (1/24)F. To get the same energy you need only apply 1/24 the force. There is a "conservation of energy" law but there is no "conservation of force".