In the process of changing a flat tire, a motorist uses a hydraulic jack. She begins by applying a force of 49 N to the input piston, which has a radius r1. As a result, the output plunger, which has a radius r2, applies a force to the car. The ratio r2/r1 has a value of 6.9. Ignore the height difference between the input piston and output plunger and determine the force that the output plunger applies to the car.

there is a hint for this problem it is to use the equation P=F/A, but that doesn't make sense.

The pressure on each pistion is the same, so the force on each piston =Pressure*area.

So the area becomes significant in transmitting force. Force transmitted will be proportional to (A2/A2) which in turn is proportional to (r2/r1)^2

I am not getting it so what am I suppose to do. Is my equation correct.

Force2=force2(r2/r1)^2 Use that.

1 answer

49Nx(6.9)^2= 2.3x10^3