Kinematics and Dynamics Flashcards
1
Q
Angstroms
A
- 10-10 m
2
Q
Nanometers
A
- 10-9 m
3
Q
Electron-volts (eV)
A
- 1 eV= 1.6 x10-19 J
- Amount of energy gained by an electron accelerating through a potiential difference of one volt
4
Q
Vectors
A
- Numbers that have both magnitude and direction
- Displacement, velocity, acceleration, force
5
Q
Scalar
A
- Numbers that have magnitude only and no direction
- Distance, Speed, pressure, mass, energy
6
Q
Vector Addition
A
- Tip-to-tail method
- Place the tail of B, to the tip of A
- The vector sum A+B is the vector joining the tail of A to the tip of B
-
Component method
1. Given and vector, V, we can find the x- and y-components by drawing a right triangle with V as the hypotenuse
7
Q
Vector Subtraction
A
- A-B=A+(-B)
- Adding a vector with equal magnitude, but in the opposite direction
- Simply flipping the direction of the vector being subtracted and then following the same rules as normal: tip to tail
8
Q
Multiplying Vectors By Scalars
A
- If a vector, A, is multiplied by the scalar value, n, a new vector, B, is created
- B= [n] A
- If n is a positive number that means B and A are in the same direction
9
Q
Multiplying Vectors
A
- To generate a scalar quantity like Work, we multiply the vectors of force and displacement and the cosine of the angle between the two vectors = Dot Product
1. A *B= [A][B] cos ø - To generate a third vector like Torque, we multiply the magnitudes of the two vectors of force and lever arm and the sine of the angle between the two vectors
1. A x B= [A][B] sinØ
10
Q
Displacement
A
- When an object in motion experiences a change in its position in space
- x or d
- Net change in position from initial to final position
11
Q
Distance
A
- The entire pathway taken
12
Q
Velocity
A
- v
- Rate of change of displacement in a given unit of time
13
Q
Speed
A
- Rate of actual distance traveled in a given unit of time
14
Q
Instantaneous Speed
A
- Will always be equal to the magnitude of the object’s instantaneous velocity, which is a measure of the average velocity as the change in time approaches zero
- V= Δx/Δt
15
Q
Average velocity
A
- vavg = Δx/Δt
- Based on displacement
16
Q
Force
A
- SI unit is a Newton (N)
- Equation: kg x m/s2
17
Q
Gravitational Force
A
- Between two objects
- Fg = G m1 m2 /r2
- G= universal gravitational constant= 6.67x10-11 Nm2 / kg2
- Would be used on MCAT
18
Q
Acceleration Due To Gravity
A
- g= 10 m/s2
- Decreases with height above the earth
- Increases the closer one gets to the earth’s center of mass
19
Q
Static Friction
A
- Always larger than kinetic friction (Always requires more force to get an object to start sliding than it takes to keep an object sliding)
- ( f<em>s</em> )
- Exists between a stationary object and the surface upon which it rests
- 0≤ fs ≤ u<em>s</em> N
- us is the coefficient of static friction (unitless quantity that depends on the 2 materials in contact)
- N is the magnitude of the normal force (Force between 2 objects in contact that is perpendicular to the plane of contact between the object and the surface upon which it rests
20
Q
Kinetic Friction
A
- Exists between a sliding object and the surface over which the object slides
- Two surfaces sliding against each other
- fk = uk N
- uk is always smaller than the coefficient of static friction
21
Q
Weight
A
- Fg = mg
- Weight of the object = Fg
- Mass of the object= m
- Acceleration due to gravity= g (9.8 m/s2 )
- Weight of an object can be though as being applied to a single point in the object = Center of mass or gravity
22
Q
Acceleration
A
- Change in velocity/ change in time
- On a graph of velocity vs. time, the tangent to the graph at any time corresponds to the slope of the graph which indicates the instantaneous acceleration
23
Q
Newtons First Law
A
- Law of inertia
- A body either at rest or in motion with a constant velocity will remain that way unless a net force acts upon it
- Fnet =ma=0
24
Q
Newtons Second Law
A
- An object of mass, m, will accelerate when the vector sum of the forces results in some nonzero resultant force vector
- Fnet =ma
25
Q
Newtons Third Law
A
- To every action, there is an equal and opposite reaction
- FAB = -FBA
26
Q
Linear Motion
A
- Examples are falling objects, balls being dropped from some starting height
- Equations:
- v=v0 + at
- x=v0 t +at2/2
- v2=v20 +2ax
- x= (average velocity)time
- Free Fall= Object falls with constant acceleration (9.8) and would not reach terminal velocity
27
Q
Drag Force
A
- An object in free fall will experience as growing drag force as the magnitude of its velocity increases
- Eventually, this drag force will be equal in magnitude to the weight of the object , and the object will fall with constant velocity = Terminal Velocity
28
Q
Projectile Motion
A
- Usually can assume vx will remain constant
29
Q
Inclined Planes
A
- Fg , parallel= mg sinØ
- Fg, perpendicular= mg cosØ
30
Q
Circular Motion
A
- Instantaneous velocity vector is always tangent to the circular path
- Centripetal force always points inwards, and generates centripetal acceleration
- Fc = mv2 /r
31
Q
No Net Force
A
- No acceleration
- Any object with a constant velocity has no net force acting on it
32
Q
Translational Equilibrium
A
- Constant velocity, both constant speed (zero or nonzero value) and a constant direction
33
Q
Torque
A
- t= r x F = rF sin Ø
- r= length of lever arm
- F = magnitude of force
- Ø= angle between the lever arm and force vectors
- Clockwise torques= negative
- Counterclockwise torques= positive
- Rotational equilibrium means that the object is not rotating at all
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