Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
THE MCAT-PHYSICS 5
FLUIDS AND SOLIDS
| Question | Answer |
|---|---|
| Which have intermolecular bonds (s,l,g)? | solids and liquids |
| WHat can withstand perpendicular forces? | gases, liquids, solids |
| What can withstand parallel forces? | solids |
| specific gravity (2) | 1.) p = p(material) / p(water) at 4C 2.) Weight / buoyant force |
| Pascal's principle | Pressure applied to enclosed fluid is transmitted equally throughout an incompressible fluid and walls of container |
| Pascal's Equation | P1-P2 = p(y2-y1)g |
| Total Pressure Equation | P(total) = P(atm) + pgh |
| When a fluid comes to rest, what forces does it experience? | normal force and gravity |
| What are extensive properties? | change with quantity of substance (mass and energy) |
| What are intensive properties? | do not change with quantity of substance (density and pressure) |
| What are incompressible and have constant density? | liquids and solids |
| Does a bucket or cup of water have a greater density? | NEITHER -mass refers to inherent mass -liquids are incompressible |
| Why does density of gas change? | gases are compressible --> change volume --> change density |
| 2 densities of water | p = 1000 kg/m^3 p = 1 gm / cm^3 |
| What is fluid pressure? | measure of the KE due to random velocities of molecules within a fluid distributed over fluid volume |
| Relate Patm and Pascals | P(atm) = 101,000 Pa |
| Does Pascal's Principle apply to gases? | NO --> gases are compressible |
| Does the shape of a container affect fluid pressure? | NO --> fluid pressure is a function of depth -pressure everywhere at a given depth in same resting fluid is constant |
| Does an ideal machine ever change work? | NO |
| 2 equations for Hydraulic Lift? | F1d1 = F2d2 F1/A1 = F2/A2 |
| What does a sunken object displace? | volume of fluid equal to its own volume |
| What does a floating object displace? | volume of fluid equal to its own weight |
| When an object is sunk, what forces act on it? | buoyant force and normal force |
| What does buoyant force equal to for a floating object? | p(medium) * V(displaced) * g |
| What does weight equal to for a floating object? | p(object) * V (object) * g |
| How are weight and buoyant force related for a floating object? | W = B |
| How to calculate percent submerged for a floating object? | Relative densities = percent submerged |
| V(object) > V (displaced) for what? | floating object |
| What is apparent weight? | Normal force |
| What does buoyant force equal to for a sunken object? | p (medium) * V (object) *g |
| What does weight equal to for a sunken object | p (object) * V (object) *g |
| How do weight and buoyant force relate to density for sunken object? | weight / buoyant force = p(object) / p(medium) |
| Under what conditions of volume and density will an object float? | V(object) > V (displaced) p(object) < p(medium |
| Under what conditions of weight, buoyant force, and density will an object sink? | W > B p(object) > p(medium) |
| What IMF account for surface tension? | H-bonds or Van der Waals |
| Water vs. ethanol: which will evaporate first / which will condense first? | -ethanol -water |
| What happens with surface tension increases? | SA decreases, volume stays the same, spherical shape, evaporate less |
| Cohesion | attraction between same molecules |
| adhesion | attraction between different molecules |
| What is viscous force? | -fluid flowing through pipe experiences forward and opposing frictional force -measure of fluids resistance to forces not perpendicular to surface |
| In a pipe, where is the fluid the fastest? Slowest? | center near edges of pipe |
| Increase temperature of fluid, what happens to viscosity of liquid and gas? | liquid viscosity decreases, gas viscosity increases |
| Flow Rate | Volume of fluid that passes through a pipe per unit time --> different from flow speed of a fluid |
| Poiseuille's Principle | Q = pi*r^4 / 8nL (P1-P2) |
| What does high BP mean in relation to Poiseuille's Principle? | Heart is generating a large P1 to produce necessary Q to get blood to tissue |
| Continuity equation | A1V1 = A2V2 |
| Why does fluid flow? | flows from region of high pressure to low pressure -->more precisely direction of fluid flow is fluid's tendency to find greatest entropy |
| What work is done on fluid? | pressure difference pushing fluid in one direction W = deltaKE + deltaPE |
| Bernoulli's Equation | P1 + 1/2pv^2 + pgy1 = P2 + 1/2pv^2 + pgy2 --> think conservation of energy! |
| What happens to pressure when there is higher velocity? | Pressure decreases |
| How to increase turbulence? (density, avg velocity, radius) | increase density, average velocity, and radius of vessel |
| Does buoyant force change with depth? | NO --> due to difference in pressure only between upper and lower surfaces |
| What kind of motion can molecules in a moving fluid thought to have? | 1.) random translational motion (contributes to fluid pressure for fluid at rest) 2.) uniform translational motion (does not contribute to fluid pressure) |
| Ideal Fluid (4 characteristics) | 1.) No viscosity 2. ) incompressible --> uniform density 3.) no turbulence 4.) irrotational flow |
| What is turbulence? | at any point in fluid, velocity may vary with time |
| Why does pressure decrease when velocity increases? | uniform translational KE is achieved by borrowing energy from random translational KE --> pressure goes down |
| What happens to pressure when you increase cross-sectional area? | increases |
| What happens to pressure when you decrease cross-sectional area? | decreases |
| What creates drag? | narrow and long pipe |
| Does narrowing a pipe increase velocity for ideal and non-ideal fluid? | YES --> less effect on non-ideal because of drag |
| Why does pressure decrease when cross-SA decreases? | A1V1 = A2V2 -faster velocity --> less opportunity to interact with walls of vessel -lower pressure |
| What does surface tension depend on? | IMF and temperature of fluid -higher temp, weaker surface tension |
| For capillary action, which way is the water pulled when adhesive forces stronger? | upward |
| For capillary action, which way is water pulled when cohesive forces are stronger? | downward |
| What is stress? | Stress = Force / Area -Force applied to object / area force is applied |
| What is strain? | Strain = change in dimension / original dimension |
| Modulus of elasticity | stress/ strain |
| What is yield point? | maximum stress point |
| WHat happens beyond yield point? | object will remain intact but will not regain original shape |
| What are the three moduli? | 1.) Young's Modulus (tensile stress) - E 2.) Shear's Modulus (shear stress) - G 3.) Bulk modulus (compression and expansion) - B |
| Young's Modulus | E = F/A // change in height / original height |
| Shear Modulus | G = F/A // change in x / original height |
| Bulk Modulus | B = change in Pressure // change in volume / original volume |
| What does density vary with? | temperature and pressure |
| What does buoyant force equal to for object immersed in a fluid? | weight of the fluid displaced by the object |
| What does it mean for something to be floating? | weight = buoyant force |
| What are the forces that act on an object floating in water | -weight and Fb in vertical direction -pressure perpendicular to all surfaces |
| Speed of flow rate for a fluid is directly / inversely proportional to cross - SA | inversely proportional |
| Items with the same volume experience the same ___ | buoyant force |
| How to calculate percent submerged? | density object / density medium |
| Calculate specific gravity with weight and Fb? | specific gravity = weight / Fb |
| Surface tension is an attractive / repulsive force? | attractive |
| Within a pipe, where does fluid flow the slowest? fastest? | edge of pipe / center of pipe |
| Greater flow rate is associated with? | a greater pressure differential |
| According to Poiseuille's Principle, what are the main things to know? | -Q = r^4 -Q = 1 / L |
| In a pipe, a lower area has a faster/slower speed while a bigger area has a faster/slower speed? | slower / faster |
| does fluid flow faster or slower through a narrowed pipe? What happens to pressure? | faster / decreases |
| Are narrow or wider paths more likely to encounter turbulence? | wider |
| What does flow rate depend on? | pressure differential |
| Elasticity progression. | Elastic limit --> ultimate tension strength --> fracture |
| What are brittle materials? | materials that have ultimate tension strengths close to fractures |
| What are ductile materials? | materials that have ultimate tension strengths far from fractures |
| Does a thicker or thinner rope increase / decrease stretching length of the rope? | increase |
| What is a large bulk modulus associated with? | solid that is difficult to deform and compress |
| What is a large tensile modulus associated with? | something that requires a lot of force to stretch |
| What is a large shear modulus associated with? | something that requires a lot of force to shear |
| Comparing two objects with different masses but same volume, which will have the stronger buoyant force? | bigger mass one |
| volume of an object submerged = | volume of fluid displaced by object |
| Relate pressure, force, area | P = F / A --> F1 / A1 = F2 / A2 |
| TRUE / FALSE: In a hydraulic system, the work done on one end is different than the work output at the other. | FALSE |
| Gauge pressure | pgh |
| TRUE / FALSE: Volume flow rate of a fluid is constant | TRUE |
| Does turbulence occur at low or high velocities? | high |
| Out of solids, liquids, gases, which are compressible? | gases |
| What is shear angle? | tan-1(change in x / height) |
| When an object floats, the ratio of densities of object / medium is =? | percent submerged |
| What is the magnitude of the weight equal to in relation to the apparent weight and buoyant force? | weight = apparent weight + buoyant force |
| Relative densities for floating vs. submerged object? | percent submerged vs. W/B ratio |
| Greater viscosity requires...? | greater pressure differential |
| What does buoyant force also equal to? What does normal force equal to? | apparent weight loss / apparent weight |
| What phases are held together by IMF? | solids and liquids |
| What phases can withstand perpendicular forces? | solid, liquid, gas |
| What phase can withstand forces NOT perpendicular? | solid |
| What phase experiences large changes in density? | gas |
| When air resistance is negligible, is projectile motion independent of mass? | YES |
| What are the 2 densities of water? | 1000kg/m^3 1g/cm^3 |
| What depth of water creates 1 at of pressure? | 10 m |
Created by:
507935299
Popular MCAT sets