Physics Flashcards
Blueprint MCAT Prep
What are the key SI prefixes?
deci (-1), centi (-2), milli (-3), micro (u, -6), nano (-9), pico (-12)
Kilo (3), mega (6), giga (9), tera (12)
What are the trigonometric functions?
SOH CAH TOA
Describe the difference between scalars and vectors
Vectors have magnitude AND direction, while scalars only have direction
When splitting velocity into X- and Y- components, which trigonometric functions do you use?
Vx = vCos()
Vy = vSin()
What is the key component of adding vectors?
X components must only add with X components, while Y components can only add with Y components
Displacement
Change in location; is a vector quantity (scalar equivalent is distance)
Velocity
Change in displacement over time; is a vector quantity (scalar equivalent is speed); area under the curve of a velocity vs. time graph is displacement
Acceleration
Change in velocity over time; is a vector quantity; area under the curve of an acceleration vs. time graph is change in velocity
What is acceleration in free fall?
-9.8 m/s2
What is Vy at the top of a projectiles trajectory?
Vy = 0
What is force
Something that causes an object with mass to accelerate
Newton’s First Law
Inertia; An object remains at rest or a constant velocity within a reference from unless an external force acts upon it
Newton’s Second Law
Defines Force; States that the total sum of forces acting on an object, also known as the net force, is equivalent to its mass times its acceleration
Newton’s Third Law
Force comes in pairs; Every action has an equal and opposite reaction
Explain some key points to remember about free body diagrams
Free body diagrams work with center of mass and draw out all forces acting on an object; Forces act from center of mass; Resolve non-perpendicular forces using trigonometry; Solve using Newton’s laws (mainly 1st and 2nd)
Static Friction
When object isn’t moving; A certain amount of force must be applied to break static friction
Kinetic Friction
When object is moving
Is more force needed to overcome static friction or kinetic friction?
Static friction
Gravitation
A force of attraction between objects with mass (know equation); Note that force of gravity is proportional to mass and inversely proportional to the square of the distance between the objects
Centripetal Force
Causes rotational motion; Common examples are gravity (eg. satellites in orbit) and tension force (mass on a string)
Hooke’s Law
Force needed to compress/stretch a spring by x is F = -kx, where k is a constant unique to each spring that represents its stiffness
Torque
Can be though of as rotational force; Know equation; Be aware of static equilibrium with torque: You may need to balance clockwise and counterclockwise forces
Work
Defined in units of energy (Joules)
What is the difference between conservative and non-conservative forces?
With conservative forces, such as gravity, work is path-independent (displacement); Non-conservative forces are path-dependent (distance) and include friction and air resistance
Mechanical Advantage
Less force –> same work
Power
Work divided by time (units are Watts)
Kinetic Energy
Know Equation; Energy due to motion
Potential Energy
Energy an object has stored within itself; Can be gravitational, elastic, electrical, or magnetic
Conservation of Energy
Energy can neither be created nor destroyed, just transferred from one form to another. This is a basic law of nature, no exceptions have been found
How do non-conservative forces affect conservation of energy?
Non-conservative forces like friction may remove energy from a specific system that we’re interested in modeling, which may be dissipated as thermal energy, but the physical law of conservation of energy is still followed
What is important to note about the equation for conservation of energy? Why is it particularly significant
Note connection between conservation of energy and the kinematic quantities of v and ∆y - this means that conservation of energy can be used to efficiently solve some kinematics problems; For some problems, you can choose between the strategies of kinematics equations or conservation of energy; Kinematics equations are needed if you need to account for time, and conservation of energy is needed if the physical setup is too complicated to apply MCAT trigonometry (eg. rollercoster)
What does the work-energy theorem link?
Work-energy theorem links work and kinetic energy; Very effective way to solve problems were you need to link work/energy with change in velocity
What does the area under the curve represent in a graph relating pressure and volume?
Work = area under the curve of a graph with pressure on y-axis and volume on x-axis; Common Application: use of pistons to compress gas
Heat
A form of energy transfer
Temperature
A way of measuring the average kinetic energy of the particles that much up a substance; Heat and temperature and NOT the same thing
What temperature does water freeze & boil in Fahrenheit; What is normal body temperature?
Water freezes at 32°F, boils at 212°F, and normal body temperature is 98.6°F
What temperature does water freeze & boil in Celcius; What is normal body temperature?
Water freezes at 0°C, boils at 100°C, normal body temperature is 37°C
Open Systems (Thermodynamics)
Open systems can exchange matter and energy with their surroundings