AP Core Concepts & Equations Flashcards
Kinematics Equation Not Given:
Delta X=
If projectile trajectory is symmetric:
angle up=angle down
speed up=speed down
time up=time down
projectile position graph=parabola curving down
projectile velocity graph=diagonal line with slope=9.8
projectile acceleration graph=flat line=9.8
If an object launches horizontally then the inital velocity in the y dimension=
0
At the higest point a projectile has ___ vertical velocity by the acceleration = ____
NO, 9.8
Define: inertia
The tendency of an object to resist any attempt to change its velocity.
Define: Force
Strength or energy as an attribute of physical action or movement.
Define: Tension
the pulling force exerted by each end of a string, cable, chain, or similar one-dimensional continuous object, or by each end of a rod, truss member, or similar three dimensional object.
Applications of Kinematics
Projectile Motion
Using one known equation (such as position) to determine the rest
Interpreting Graphs
ΣF=
ma
Newtons Second Law
ΣF=ma
Friction=
µn
Centripetal Acceleration=
v2/r
Force of a Spring=
-kx
Hookes Law
Fspring= -kx
Only ____ springs obey Hookes Law
Linear
Applications of Newton’s Laws
(8: F,F,P,R,S,T,T,R)
Free body diagrams that are balanced
Free body diagrams that are accelerating
Pulleys
Ramps
Satellites (Centripetal Acceleration)
Turning Corners
Tension in a rope attached to a circling object
Resistive Forces (Air resistance, drag, etc.)
x=
y=
Ø=
x=rcosØ
y=rsinØ
Øtan-1(y/x)
Newton’s Three Laws
Law 1: Balanced Forces (Object in motion stays in motion…)
Law 2: Unbalanced Forces (F=ma)
Law 3: Pair Forces (action, reaction)
If you change your axis to match a ramp and the angle of the ramp is measured from the horizontal, then. . .
. . . sin and cos switch dimensions.
Simultaneous equations are often easier to solve using _____ than they are using _____.
elimination (adding, subtracting, or dividing), substitution
______ friction is stronger than ______ friction.
Static, Kinetic
Resistive forces come in the form:
F= -bv where b=drag coefficient, v=velocity
Because resistance increases with speed the object will eventually reach a ___________.
terminal velocity.
Terminal Velocity:
a=
ΣF=
bv=
Vt=
(if gravity is involved)
a=0
ΣF=0
bv=mg
VT=mg/b
To solve a resistive system:
ΣF=mg-bv
ma=mg-bv
a=(mg-bv)/m
dv/dt=(mg-bv)/m
dv/dt=g-bv/m
STOP: GO OVER LONG 16 STEPS
Solution of Resitive System with Gravity
V=mg/b(1-e-bt/m)
Object in Free Fall w/ Air Resistance
Position Graph
*assuming down is positive
Curves at first, then approaches a straight diagonal line with slope=Terminal Velocity
Object in Free Fall w/ Air Resistance
Velocity Graph
*assuming down is positive
Slope=9.8 but then curves towards a horizontal asymptote (terminal velocity)
Object in Free Fall w/ Air Resistance
Acceleration Graph
*assuming down is positive
Starts at 9.8 and curves towards a horizontal asymptote (a=0)
Object in Free Fall w/ Air Resistance
Projectile
*assuming down is positive
Time up < Time down because on the way down air resistance acts like a parachute
Won’t go as high, crests before down time.
p (momentum)=
mv
J=
* if force is constant
FΔt