Bennett Mechanical Test Fluid Mechanics and Hydraulics 2 ā Questions and Answers
Question 1: In a hydraulic system, a small piston with area 2 inĀ² pushes against a large piston with area 10 inĀ². If 50 lb is applied to the small piston, what force is produced at the large piston?
- 10 lb
- 50 lb
- 250 lb (Correct answer)
- 500 lb
Correct answer: 250 lb
Pressure is equal throughout, so force scales with area: (50/2) Ć 10 = 250 lb.
Question 2: Pascal's principle states that pressure applied to a confined fluid is transmitted:
- Only in the direction of the applied force
- Equally in all directions (Correct answer)
- Stronger near the bottom
- Only along the container walls
Correct answer: Equally in all directions
Pascal's principle says confined fluid transmits applied pressure undiminished in every direction.
Question 3: Two connected pistons must conserve volume of fluid. If the small piston moves 10 inches and has area 2 inĀ², how far does a 10 inĀ² piston move?
- 2 inches (Correct answer)
- 5 inches
- 10 inches
- 50 inches
Correct answer: 2 inches
Volume is equal: 2 Ć 10 = 10 Ć d, so d = 2 inches.
Question 4: Which property allows hydraulic systems to multiply force?
- Liquids are compressible
- Liquids are nearly incompressible (Correct answer)
- Liquids have low density
- Liquids evaporate under pressure
Correct answer: Liquids are nearly incompressible
Because hydraulic fluid is nearly incompressible, applied pressure transmits directly into output force.
Question 5: A car lift uses a 1 inĀ² input piston and a 100 inĀ² output piston. To lift a 2,000 lb car, how much force is needed on the input?
- 10 lb
- 20 lb (Correct answer)
- 200 lb
- 2,000 lb
Correct answer: 20 lb
Force divides by the area ratio: 2,000 Ć· (100/1) = 20 lb.
Question 6: Pressure in a fluid is defined as:
- Force times area
- Force divided by area (Correct answer)
- Area divided by force
- Mass times velocity
Correct answer: Force divided by area
Pressure equals force per unit area (P = F/A).
Question 7: Hydraulic force multiplication does NOT increase:
- Output force
- Pressure transmission
- Total work or energy (Correct answer)
- Mechanical advantage
Correct answer: Total work or energy
Force is multiplied but the larger piston moves less, so work in equals work out.
Bennett Mechanical Test Fluid Mechanics and Hydraulics 2
In a hydraulic system, a small piston with area 2 inĀ² pushes against a large piston with area 10 inĀ².
If 50 lb is applied to the small piston, what force is produced at the large piston?