Question 3
In a hydraulic press the small piston has an area of 5 cm2 and the large piston an area of 100 cm2. If a force of 30 N is applied to the small piston, what force acts on the large one?
The right answer is the one marked above.
600 N. The pressure at the small piston is 30 N ÷ 5 cm2 = 6 N cm−2. That same pressure reaches the large piston, so the force is 6 × 100 = 600 N.
30 N is what you get by assuming the force itself is transmitted. The ratio of the areas is 100 ÷ 5 = 20, so the force is multiplied by 20.