U3f – L3 1.Sketch the relationship between Pressure and Volume 2.Sketch the relationship between 1/Pressure and Volume March 25, 2011 DRILL

U3f – L3 DRILL

U3f – L2 Robert Boyle ( ) – from Ireland; chemist, physicist, and inventor Boyle’s Law – the pressure and volume of an ideal gas are inversely proportional Increase Pressure –Decrease Volume Increase Volume –Decrease Pressure PV = k P 1 V 1 = P 2 V 2 Boyle’s Law

U3f – L2 Back to your chart. What do you notice about the values for P x V? Under constant temperature, the product of pressure and volume for a fluid is a constant. Boyle’s Law: P V = k Principles of Fluid Technology

U3f – L3 Technology – the application of knowledge, tools, and skills to solve problems and extend human capabilities. Technology System – a group of subsystems working together to solve problems and extend human capabilities. Core Technologies – several engineering resources that are the “building blocks” of all technology systems. Volume – how much space an object occupies Force – a push or pull Pressure – a force applied over an area Closed System – a system in which no fluid can enter or leave. Open System – a system in which a fluid can enter or leave. Fluid – a substance (as a liquid or a gas) that conforms to the outline of its container Fluid Technology – the technology of using fluid, either gas (pneumatics) or liquid (hydraulic), to apply force or to transport. Definitions

P = F / A (Pressure = Force / Area) PV = k (Pressure x Volume = Constant) P 1 V 1 = P 2 V 2 (Initial P x Initial V = Final P x Final V) Worksheet #3 U3f – L3

A gas system has initial pressure and volume of 80 psi and 6 L. If the volume changes to 10 L, what will the resultant pressure be in psi? Worksheet #4 Step 1: Write given information P1 = 80 psi V1 = 6 L P2 = ? V2 = 10 L Step 2: Write the formula and solve P 1 V 1 = P 2 V 2 (80 psi) x (6 L) = P2 x (10 L) 480 psi*L = P2 x (10 L) 10 L 10 L P2 = 48 psi

U3f – L3 A sample of hydrogen gas is compressed from 300 cm 3 to 2.5 cm 3. Its pressure is now 5 psi. What was the original pressure of the helium? Worksheet #5 Step 1: Write given information P1 = ? V1 = 300 cm 3 P2 = 5 psi V2 = 2.5 cm 3 Step 2: Write the formula and solve P 1 V 1 = P 2 V 2 P1 x (300 cm 3 ) = 5 psi x (2.5 cm 3 ) P1 x (300 cm 3 ) = 12.5 psi* cm cm cm 3 P1 = psi

U3f – L3 1.The diagram below illustrates how hydraulic brakes in a car work. The pedal must be pressed with a force of 8 lbs. The surface area of the piston connected to the pedal is 1 square inch. If the surface area of the piston connected to the other end of the brake line is 1.5 square inch, what is the force applied to that piston? P 1 = P 2 Problem 7 P1 = F1 / A1P2 = F2 / A2

U3f – L3 Problems Solution: Step 1: Write given information P1 = ?P2 = ? F1 = 8 lbs.F2 = ? A1 = 1 in 2 A2 = 1.5 in 2 Step 2: Write the formula and solve for the unknowns P1 = F1 / A1 P1 = (8 lbs) / (1 in 2 ) P1 = 8 psi P1 = P2 = 8 psi F2 = 8 psi x 1.5 in 2 = 12 lbs. P2 = F2 / A2 F2 = P2 x A2

U3f – L3 Problems P1 = 8 psi F1 = 8 lbs A1 = 1 in 2 P2 = 8 psi F2 = 12 lbs A2 = 1.5 in 2 What is the mechanical advantage of this system? MA = L / F MA = (12 lbs)/ (8 lbs) MA = 1.5

Complete the fluid technology problem sheet. U3f – L3