Fluid Mechanics and Hydraulics Flashcards
7 cards from real Bennett Mechanical Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fluid Mechanics and Hydraulics flashcards as text
In a hydraulic system, a small piston with area 2 in² pushes against a large piston with area 10 in². If 50 lb is applied to the small piston, what force is produced at the large piston?
Answer: 250 lb
Pressure is equal throughout, so force scales with area: (50/2) × 10 = 250 lb.
Pascal's principle states that pressure applied to a confined fluid is transmitted:
Answer: Equally in all directions
Pascal's principle says confined fluid transmits applied pressure undiminished in every direction.
Two connected pistons must conserve volume of fluid. If the small piston moves 10 inches and has area 2 in², how far does a 10 in² piston move?
Answer: 2 inches
Volume is equal: 2 × 10 = 10 × d, so d = 2 inches.
Which property allows hydraulic systems to multiply force?
Answer: Liquids are nearly incompressible
Because hydraulic fluid is nearly incompressible, applied pressure transmits directly into output force.
A car lift uses a 1 in² input piston and a 100 in² output piston. To lift a 2,000 lb car, how much force is needed on the input?
Answer: 20 lb
Force divides by the area ratio: 2,000 ÷ (100/1) = 20 lb.
Pressure in a fluid is defined as:
Answer: Force divided by area
Pressure equals force per unit area (P = F/A).
Hydraulic force multiplication does NOT increase:
Answer: Total work or energy
Force is multiplied but the larger piston moves less, so work in equals work out.