Self-Test C-1.12: Use Pascal’s Theory of Pressure and Force
Complete Self-Test C-1.12 and check your answers.
- A piping apprentice accidentally strikes a pipe with the end of a pickaxe while trying to expose a gas line. If the pickaxe strikes with a force of 2,000 N and the end of the pickaxe measures 0.02 m by 0.01 m, how much pressure was placed on the pipe by the pickaxe?
Answer: MPa
- A carpenter hammers a nail with a force of 45 N with every stroke. The head of the nail has a surface area of 0.002 m2. How much pressure is exerted on the nail head with each stroke?
Answer: kPa
- A box has a weight of 480 lb., and the bottom of the box is 12 in.2 What is the pressure the box exerts on the floor?
Answer: psi
- A heating boiler weighs 2,400 newtons and has a base that is 4 metres by [latex]\frac{1}{2}[/latex] metre. What is the pressure the boiler exerts on the floor?
Answer: kPa
- What is the weight of an object that has a base that is 14.5 square inches and that exerts a pressure of 21 pounds per square inch?
Answer: lb.
- What does a car weigh if its tires cover an area of 4.3 square feet and each tire exerts a pressure of 975 pounds per square foot on the ground?
Answer: lb.
- To pop a balloon, you stab it with a pencil. If the area of the pencil tip is 0.001 in.2 and the pressure applied by the pencil to the balloon is 10 [latex]\frac{\text{lb.}}{\text{in.}^2}[/latex], how hard (what force) must you push on the pencil to make the balloon pop?
Answer: lb.
- A round rod weighs 38 lb. If the rod is stood on end so it pushes down on the floor with a pressure of 12.66 [latex]\frac{\text{lb.}}{\text{in.}^2}[/latex], how many square inches is the end of the rod?
Answer: in.2
- If the inside of a container has a surface area of 20 in.2, what will be the pressure on each square inch of the container if 117.6 pounds of force are applied to the container?
Answer: psi
- The pressure of a nail was measured at 350 Pa. What force is exerted by the nail if the surface area is 0.13 m2?
Answer: N
- The pressure in a boiler is 20 kPa. If the area of one end of the shell is 0.6 m2, what is the force on that end?
Answer: N
- A student exerts a force of 304 N on a gas syringe. The pressure gauge reads a pressure of 40 kPa. What is the cross-sectional area of the plunger of the syringe?
Answer: m2
- A pressure cooker has a pressure of 1,013,250 Pa inside. The lid has an area of 0.2 m2. What is the force on the lid?
Answer: N
- A water main is directed around a sharp 90-degree bend. The force produced is equal to 1,750 lb. The soil engineer’s report says that the sandy soil in the area will only withstand 12 psi before it may compact. How much area must a thrust block cover in order to comply with the soils report?
Answer: in.2
- What would be the pressure exerted by four feet of water depth?
Answer: psi
- What would be the pressure exerted by 7.5 m of water depth?
Answer: kPa
- What height of water is required to exert a pressure of 47 psi?
Answer: ft.
- What height of water is required to exert a pressure of 0.0361 [latex]\frac{\text{lb.}}{\text{in.}^2}[/latex]?
Answer: in.
- What height of water is required to exert a pressure of 231.52 kPa?
Answer: m
- How much pressure would a column of mercury 14 inches high exert?
Answer: psi
- What would be the pressure at the bottom of a pipe full of water that is 10″ in diameter and is 15′ high?
Answer: psi
- What would be the psi at the bottom of a tank full of water [latex]25\text{' long} \times 15\text{' wide} \times 8\text{" deep}[/latex]?
Answer: psi
- What would be the height of a water column needed to produce a pressure of 12.8 psi in a 6″ pipe?
Answer: ft.
- What would be the total force on the bottom of a tank full of water that is [latex]4\text{' long} \times 6\text{' wide} \times 26\text{" high}[/latex]?
Answer: lb.
- What would be the total force at the bottom of a 4″ soil or waste stack 16′ high?
Answer: lb.
Answer Key: Self-Test C-1.12 is on the other page.
