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A hydraulic press has its larger piston (diameter 35 cm) located 1.5 m above the smaller piston (diameter 10 cm). A 20 kg mass rests on the smaller piston. The oil filling the press has density 750 kg/m³ and g = 9.8 m/s². Find the force the larger piston exerts on the load placed on it.
- 5 * 10³ N
- 1.3 * 10³ N
- 3.7 * 10³ N
- 4.8 * 10³ N
Correct answer: 1.3 * 10³ N
Solution
Pressure produced by the load on the small piston is transmitted through the oil. Because the large piston is higher by 1.5 m, the pressure there is reduced by the hydrostatic term rho*g*h. Multiplying the net pressure by the large piston area gives the upward force on the load.
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