PAT Flashcards
Geometric sequence to n
a(1-r^n) / (1-r)
Geometric sequence to infinity
a / (1-r)
SUVAT (T is unknown)
v^2 = u^2 + 2as
SUVAT (A is unknown)
s = t (u+v)/2
SUVAT (V is unknown)
s = ut + 1/2 at^2
SUVAT (S is unknown)
v = u + at
Newton’s first law
an object in motion stays in motion if no unbalanced forces act on it
Newton’s second law
F = ma
Newton’s third law
When two objects interact, they apply forces to each other of equal magnitude and opposite direction
Circular motion acceleration ( 2 equations)
a = v^2 / r & a = w^2 r
Terminal velocity of a falling object
Velocity at which an objects air resistance/friction matches its weight
Hooke’s law
Force = -kx
Potential energy of a spring
E = 1/2 kx^2
Work done
E = Fd
What do waves do?
Transfer energy without net movement of matter
Examples of longitudinal waves
Sound waves
Ultrasound
P waves
Examples of transverse waves
Electromagnetic
S waves
Amplitude
Maximum dispacement (m)
Frequency
Oscillations per second (Hz)
Period
Time taken to complete one oscillation (s)
Wavelength
Distance from identical points on two adjacent waves (m)
Wave formula
wave speed = wavelength x frequency
Law of reflection
Incident angle = angle of reflection
Refractive index
n = speed of light / speed in substance
Snell’s Law
n1sinx1 = n2sinx2
Critical angle
sinc = n2 / n1
Conditions for total internal reflection
Travelling to a less dense medium (n2 < n1)
Angle of incidence > critical angle
Interference
When two waves meet their amplitudes are added
Constructive interference
Occurs when waves meet in phase
Destructive interference
Occurs when waves meet out of phase
Charge
current x time
Energy =
potential difference x charge
2 power equations
voltage x current
energy / time
Series circuits
Current is the same throughout the circuit
Resistance of each component is added
Voltage is shared between components
Parallel circuits
Current divided between paths
1/RT = 1/R(1) + 1/R(2) …
Voltage in each branch is equal to total voltage
Force between two point charges
Force= kQ1Q2 / r^2
Force on a point charge in an electric field
Force = Charge x Electric field
Photoelectric effect equation
hf = work function + max kinetic energy
Force between two masses
F = GM1M2 / r^2
Geostationary orbit
Moves with the same angular frequency as the object it is orbiting
Capacitators
TBA
Diffraction
TBA
