MCAT Physics formulas and concepts
1000
1 g/cm^3 = ???? kg/m^3
1
1 g/mL = ??? g/cm^3
magnitude
Although pressure is a scalar quality, when two areas of different pressure meet, the net forces can result in a net acceleration with xxxxx
By definition, if an object has a constant velocity, then both the object's speed and its direction of motion are constant. Therefore the object CANNOT have a varying speed if its velocity is constant.
Can an object have a varying speed if its velocity is constant?
Yes basically its once again all in the perspective. If you deem the direction they're going on the coordinate plane as negative and both are going in the same direction then both are negative
Can you have a negative velocity and negative acceleration at the same time?
Yes These questions are all about perspective. you can have an object going in the negative direction (upward velocity) while acceleration is opposing it downward (positive acceleration)
Can you have negative velocity while still having positive acceleration ?
U = -W
For adiabatic processes, the what does the first law of thermodynamics reduce into ?
9.8m/s^2
For any pulley problem, your acceleration will NEVER be more than
U = Q
For isochoric processes, the what does the first law of thermodynamics reduce into ?
Q = W
For isothermal processes, the what does the first law of thermodynamics reduce into ?
We know that its acceleration is toward the center, and we know it is equal to v^2/r thus per newtons second law, its simply: mass of object x v^2/r
How do we find the centripetal force of an object in uniform circular motion?
If you're using the equation with a test point, its always gonna oppose that test charge and emanate the opposite direction If you're using the equation that simply tells you what the Ef is at a certain distance, then the magnitude is of course going to emanate in the same direction of that spot.
How do you determine the direction of the magnitude of electric field?
It is not! Flow rate (volume/time) is independent of a change in cross sectional area
How is flow rate affected by a change in cross sectional area ?
It is directly proportional to the change in cross sectional area V1A1 = V2A2 where v are speed and A are the cross sectional areas
How is linear speed of a fluid affected by a change in cross sectional area ? How is it quantified? (continuity equation)
parallel or antiparallel
ONLY forces xxxxx or xxxx to the displacement vector (usually velocity) will do work (transfer energy)
perpendicular to one another
One unique aspect about uniform circular motion is that the centripetal force and velocity are xxxxx
decreases, negative
Positive charges will spontaneously move in the direction that xxxxx their electric potential and produce xxxx voltage (potential difference)
Kinetic Energy
WORK IN MOTION IS BASICALLY ....
In picture but make sure to recite them
What are the 4 useful kinematic equations for constant acceleration?
Torque = r x F sin(theta) where r is the distance from the fulcrum, F is the magnitude of the force. a lot of the time you'll set these equal to each other to find the optimal distance to balance a seesaw
What are the formulas for applying torque (primarily for
N x meters
What are the units for joules performed in work?
If it is concave, it means that its adhesive properties are stronger than its cohesive forces If it is convex, it means that its cohesive properties are stronger than its adhesive forces
What does it mean if a meniscus is concave (downwards) vs convex (upwards)
(Kg x M^2) / (s^2)
What does the joule break down into unit wise?
Its basically an equation that is a conservation of energy it states the more energy that is dedicated toward movement means less fluid is being dedicated to providing static pressure
What is Bernoulli's principle and how is it represented mathematically ?
Every electrical source charge generates what is called an electric field around it. If you introduce another charge near this,the electric field will introduce a force to it equal to: E = F / q where E is the strength of the electric field, F is the force exerted on the particle by the source charge and q is the magnitude of the test charge of the particle itself. Notice this will have units of N/C. If you do not have a test charge, you will have to calculate it using the formula below: E = kQ/r^2 Where Q is net source charge magnitude, k is the coulomb's constant (9x10^9 N x m^2 / C^2) and r is is the distance between the charges
What is an electric field and what is the mathematical formula for it? How can you use it to quantify the force occurring at that point?
Coulomb's law states that when electrons or protons are near eachother they generate an electrostatic force (Fc) : Fc = kq1q2 / r^2 where k is the coulomb's constant (9x10^9 N x m^2 / C^2) q1 and q2 are the magnitudes of the two charges and r is the distance betweeen the two charges in meters The answer will be in Newtons
What is coulombs law as it pertains to electrostatic forces and what is its formula ? What will the answer be in units
This is primarily applied to springs that are stretched and compressed The mathematical formula is: U = 1/2kx^2 where k is the spring constant, and x is the magnitude of displacement from equilibrium NOTICE THAT COMPRESSING A SPING TO HALF ITS ORIGINAL LENGTH INCREASES POTENTIAL ENERGY 4 FOLD
What is elastic potential energy ? What is it usually applied to and what is the mathematical formula?
Electric potential is a number expressed as J/C that tells us essentially how much electrical potential energy (work) a test charge would give if we put it @ a certain distance from the stationary field Essentially It is equal to the electric field multiplied by the distance from the field V = Ed, which when you multiply out will be kQ/r Notice it depends on the electric potential and distance from that potential, it does not depend on the magnitude of the charges.
What is electric potential (V) and how is it different from electric potential energy?
It is the amount of potential energy a particle has in relation to other field energies. It is quantified by: U = kQq/r Where Q is the charge of the stationary field, q is the charge of the particle and r is the distance between them. If charges are like, then the potential energy will be positive. if charges are opposite, the potential energy will be negative
What is electrical potential energy and how is it mathematically expressed?
Mechanical advantage is basically a ratio of work you didnt have to do by using a machine Mechanical advantage = Force with machine / Force without
What is mechanical advantage and how is it expressed mathematically ?
An object at rest will tend to stay at rest unless acted upon by an external force Fnet = ma where the units of force are Netwons
What is newton's first law? How is it represented mathematically? what are the units of force?
An object of mass m will accelerate when the vector sum of the forces results in some nonzero resultant force and this net force and acceleration must be in the same direction Fnet = ma
What is newton's second law? How is it represented mathematically?
It assumes that fluids (liquids and gases) are incompressible, and thus when acted upon by a change in pressure, that change in pressure is distributed to every portion of the fluid F1/A1 = F2/A2 and remembering that P = F/A, we can see that the pressures between the two are equal. The second part which has more force does so by displacing over a smaller distance.
What is pascal's principle as it pertains to fluid hydrostatics ? How is it represented mathematically?
Power is the rate at which energy is transferred from one system to another per unit time (change in E/Change in time) The formula is P = change in energy (work) / time The units are watts (J/s)
What is power in physics and what is it equal to?
it is ratio of the density of that substance to the density of water at 4 C, which is 1 g/cm^3 Thus if you're given a density in g/cm^3, simply divide it by 1, if given a density in kg/m^3, simply divide by 1000
What is specific gravity and how do you calculate it ?
it is the total pressure that is exerted on an object that is submerged in a fluid (which are both liquids and gases) P = Pinitial + pgz where P is the absolute pressure, Pinitial is the incident pressure (which is usually atmospheric pressure but can be different if you're in a system that has a different pressure) p is the density of the fluid g is gravity's acceleration z is the depth from the surface in meters
What is the definition of absolute (hydrostatic) pressure? What is the formula ?
it is a ratio of force per unit area P = F/A where F is force in newtons and A is area in m^2 thus the units for pressure are pascals, which are equivalent to 1 N/m^2
What is the definition of pressure and how is it expressed mathematically? what are its units
Average velocity is a total displacement divided by the total time where as average speed is the total distance traveled divided by the total time
What is the difference between average velocity and average speed?
W = F d cos (theta) where F i the magnitude of applied forces, d is the distance of displacement, and theta is the angle between the applied force the unit is joules
What is the equation for work done over a certain distance ? what will the units of the answer be in ?
F1D1 = F2D2 remember that this is only possible bc this is an isobaric process
What is the equation for work of hydraulic lift
V = kQ/r, (same as U/q) It can also be expressed as: J/C are the units For a positive charge, V is positive For a negative charge, V is negative
What is the formula for electric potential (V)? what will your units be expressed in and will they be negative or positive
KE = 1/2mV^2 where m is the mass in Kg, v is SPEED in m/s The unit is the joule
What is the formula for kinetic energy and what are its units?
g x sin(theta) Notice that the larger the angle, the faster the object will accelerate down the ramp (which makes total sense)
What is the formula to determine the acceleration of an object on a ramp?
The normal force is equal to g cos (theta) with g being the force of gravity If friction is applied, you'd add the mass of the box to the equation
What is the formula to determine the normal force of an object on a ramp?
hypotenuse x cos(theta)
What is the formula to find the X component given the angle and hypotenuse?
hypotenuse x sin(theta)
What is the formula to find the Y component given the angle and hypotenuse?
Archimedes' principle is all about buoyancy It is basically saying a the mass of a fluid displaced exerts a force equal to its weight against the submerged object Dfluid x Vsubmerged x g Where D is the density of the fluid, V is the % of the object's volume submerged and g is the acceleration of gravity
What is the premise behind Archimedes' principle and how is it expressed mathematically
It is an equation to calculate the flow rate (volume/second) NOT speed basically there are 4 important things - an increase in pipe radius will raise the flow by a power of 4 - an increase in pressure gradient has a direct relationship with increasing the flow rate - increasing the length of a pipe will proportionally decrease the flow rate - increasing viscosity will proportionally decrease the flow rate
What is the premise behind poiseulle's law? We dont need to know the formula behind it but what are the big takeaways behind it ?
It basically says the net work done by forces acting on an object will result in an equal change in the objects kinetic energy Wnet = Kfinal - Kinitial It allows us to calculate work done without knowing the magnitude of forces acting on an object
What is the premise behind the work energy theorem and how is it expressed mathematically? how is it useful
The pascal second Pa x s = N x s / m^2
What is the units for viscocity?
Total mechanical energy is the sum of an objects potential and kinetic energy. E = U + K where U is potential energy, K is kinetic energy NOTICE THIS FORMULA DOES NOT ACCOUNT FOR ENERGY LOST VIA NONCONSERVATIVE FORCES
What is total mechanical energy conceptually? What is the formula for total mechanical energy ?
Voltage itself is the difference in electric potentials between two spots Va and Vb and is quantified from the following equation: ΔV = W/q Where W is the amount of work it took to move a to b (will be given in J) and q is the charge of the test particle. For positive test charges, your voltage will be negative because q is positive and this W will be negative For negative test charges, the voltage is positive bc q is negative and Wab will be negative
What is voltage (potential difference) ? How is it expressed mathematically? Explain how to know how the signs of the equations will be
acceleration a = v^2/r
When it comes to the kinematics of uniform circular motion, an Object moving in a circle of radius R at a constant speed V has an xxxxx whose direction is toward the center of the circle and is quantified by....
+
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR HEAT (Q)] HEAT FLOWS INTO SYSTEM
-
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR HEAT (Q)] HEAT FLOWS OUT OF SYSTEM
-
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR INTERNAL ENERGY] DECREASING TEMPERATURE
+
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR INTERNAL ENERGY] INCREASING TEMPERATURE
-
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR WORK (W)] WORK IS DONE BY THE SYSTEM
+
[INDICATE WHETHER THE THE SIGN IS POSITIVE OR NEGATIVE FOR WORK (W)] WORK IS DONE ON THE SYSTEM
1
a change in 1 degree celsius is equal to change in xxxx degrees of Kelvin
first you have to solve for the x and y components using Fsin(theta) and Fcos(theta) then depending on what the question is asking you'll probably likely have to solve for T in the Y compnents and then plug into X and solve for distance.
briefly go over how to do kinematic equations involving the launching of something at an angle
Essentially, this is an extension of newtons second law. The tension in a rope that is accelerating upward will not only have to accommodate the weight but also the extra force it takes to accelerate upward
how do you conceptually solve for the forces of tension in the string in an elevator?
simply convert to its mass by multiplying by its total volume and then multiply by the gravity constant
how do you convert from density to weight ?
basically youll set the Vy to zero and solve for time then you'll plug y into the
how do you find the maximum height of for a problem involving the launching of something at an angle
basically you first solve for how long it is in the air using the Vy kinematic equation Vy = V0 + at Once you solve for that, you know that the object isnt accelrating in the X direction, thus you simply need to plug need to multiply its initial velocity by the time To find the angle it makes when launghed you set up a triangle, Its X component will simply be its horizontal component, its y component witll be the acceleratoin of gravity times the amount of time falling.
how do you go about solving problems where an object is launching off a high surface with an initial horizontal velocity ?
instantaneous velocity
instantaneous speed will always be equal to the magnitude of the object's xxxx
scalar
is pressure a scalar or vectors?
temperature
it is important to remember that during phase changes there is no change in xxxx
field lines are imaginary lines that represent how a positive test charge Would move in the presence of the source charge. Positive charges have electric fields that radiate outward while negative charges have electric fields that radiate inward They point away from positive charge and towards negative charge The thicker they are the stronger the electric field
what are field lines ? What do they convey
1 x 10^5 pascals = 760 torr = 1 atm
what are the conversions for pascals to torr to atmospheres
work and heat
what are the only two process functions ?
coulomb's/sec
what are the units for an ampere
1 N = 1 kg m/ s^2
what are the units for netwons
g/mL or g/cm^3
what are the units of density ?
N/m^2
what are the units of pascals?
212 F
what is BP in fahreinheit?
30C and 98.6F
what is biologic temeperature in both F and C
it is the transfer of heat by physical There MUST be physical contact for this to occur
what is conduction in terms of heat transfer?
it is the transfer of heat by the flow of liquids and gases only
what is convection in terms of heat transfer?
it is the difference between absolute pressure inside a system and atmospheric pressure outside the system Patm - (Pinitial + pgz) Thus, if Pinitial is = Patm, then it is simply expressed as: guage pressure = pgz p is the density of the fluid g is gravity's acceleration z is the depth from the surface in meters
what is gauge pressure ? how is it expressed mathematically ?
transfer of heat via electromagnetic radiation
what is radiation in terms of heat transfer?
It is in the photo
what is the formula for acceleration of an atwood (pulley machine) that is only working with gravity (no pulleys)
Fc = (mv^2 / r) where m is the mass of the object, v is the velocity and r is the radius of the circular path
what is the formula for centripetal force ?
ΔS = Q/T where Q is the heat gained or lost and t is the temperature in kelvan
what is the formula for entropy (s) ?
Fg = Gm1m2/r^2 where G is the gravitational constant (6.67 x 10^-11 Nxm^2/kg) m1 and m2 are the masses of each object r is the distance between their centers of mass THE IMPORTANT THINGS TO SEE IS THAT THE MASSES WILL HAVE A PROPORTIONAL RELATIONSHIP (IF M1 IS TRIPLED, FG WILL TRIPLE) WHEREAS THE DISTANCE WILL HAVE AN EXPONENTIAL EFFECT. (IF R IS HALVED then Fg will incrrease by an exponent of 2)
what is the formula for gravitational force and what are the important proportionalities that come from it?
U = mgh where m is mass in Kg, g is the acceleration in gravity and h is the height above the point of interest The h can be negative if below the point of interest
what is the formula for gravitational potential energy?
Fs = Us x N where N is the normal force (usually just the mass of the object times gravity 9.8m/s^2) Us is the friction coefficient which will be provided
what is the formula for static friction (Fs) and how do you find each component ?
aLΔT where a is coefficient of linear expansion, L is the original length and T is the change in kelvin or celsius
what is the formula for thermal expansion of Length of a substance ?
ΔV = BVΔT Where B is the coefficient of volumetric expansion and V is the original volume and T is the change in kelvin or celsius
what is the formula for thermal expansion of volume of a substance ?
FIRST OF ALL THIS CAN ONLY BE CALCULATED IF THE THING IS HELD AT A CONSTANT PRESSURE. If so.... W = PΔV the answer will be in joules
what is the formula to determine the amount of work done by volume expansion of a gas?
e = 1.6 x 10 ^-19 Coulombs
what is the fundamental amount of charge for a proton and electron (separately not the sum)
The newton Kg x N / S^2
what is the typical unit for force? what are its units ?
(9x10^9 N x m^2 / C^2)
what is the value for coulomb's constant?
Conductors insulators
xxxxx spread charge evenly amongst their surface while xxxxx do not
