Headstart Flashcards
What is the equation for velocity, using displacement and time
V =s/t
V - ms^-1
S - m
t - s
What is the equation for acceleration using velocity and time?
a = (v-u)/t
a - ms^-2
v - ms^-1
u - ms^-1
t - s
What is the value of acceleration due to gravity?
-9.81 ms^-1
How to find the velocity form a displacement-time graph?
Velocity = gradient = change in displacement/change in time
What is Newton’s second law?
F = m x a
F - N
m - kg
a - ms^-2
What is the equation for kinetic energy
E(k) = 0.5 x m x v^2
E(k) - J
m - kg
v - ms^-1
What is the equation for gravitational potential?
E(p) = m x g x h
E(p) - J
m - kg
g - 9.81
h - m
What is the principle of energy?
Energy cannot be created or destroyed- it can only be converted into other forms
What is the equation for work done involving force and distance?
W = F x s
W - J
F - N
s - m
What does work done mean in regards to GPE and KE?
Work done = increase in GPE and KE
What is power?
Power is the work done per unit time
What is the equation for power using work done?
P = W/t
P - W
W - J
t - s
What is the equation for power using force?
P = F x v
P - W
F - N
v - ms^-
Note: ONLY true when object is moving at constant speed in same direction as the force
What is Hooke’s Law?
F = k x difference in l
F - N
k - Nm^-1
l - m
What is the limit of proportionality?
The maximum force that can be applied to a spring and it will still extend proportionally
What is the equation for electric current?
I = Q/t
I - A
Q - C
t - s
What is the equation for potential difference across components?
V = W / Q
V - V
W - J
Q - C
What is Kirchhoff’s First Law?
The sum of the currents going into the junction = the sum of the currents going out —> current is same everywhere in series circuit, shared in parallel circuit
What is Kirchhoff’s 2nd Law?
For any closed loop in a circuit, the sum of the potential differences across the components equals the potential difference of the power supply
What is the equation for resistance?
R = V/I
R - ohms
V - V
I - A
What is Ohms Law
Potential difference is proportional to Current when temperature is constant. (Eg of ohmic component - resistor
What does a Current-Pd (I-V) graph look like for an ohmic component?
Straight line, with gradient equal to 1/resistance of component, goes through origin
What does a current-pd (I-V) graph look like for a non-ohmic component look like?
1) filament lamp - as pd across lamp increases, filament gets hotter, resistance increases
2) diode - only let current flow one way, resistance is very high in other direction
What is power?
Power is the rate of transfer of energy
What is the equation of finding power from current and pd
P = V x I
P - W
V - V
I - A
What is the equation for power using current and resistance
P = V^2/R
P - W
V - V
R - ohms
Define transverse waves
Transverse waves vibrate at 90° to direction of travel
Define longitudinal wave
Vibrate parallel to direction of travel
Define displacement
How far a point on the wave has moved from its equilibrium position
Define amplitude
The largest possible displacement from the equilibrium position
Define wavelength
The length of one wave cycle
Define period
The time taken for a while cycle to complete or pass a certain point
What is the equation for frequency
f = 1/T
f - Hz
T - s
What is the wave equation for speed, frequency and wavelength
v = f x wavelength
v - ms^-1
f - Hz
Wavelength - m
What is the angle of incidence
The angle of the incoming wave
What is the angle of reflection
The angle of the reflected wave
What is the law of reflection?
Angle of incidence (i) = angle of reflection (r) I
What happens when an EM wave enters a denser medium?
It bends towards the normal
What happens when an EM enters a less dense medium
It bends away from the normal
What is Snell’s Law?
When an incident ray travelling in air meets a boundary with another material, the angle of refraction of the ray, r, depends on the refractive index of the material and the angle of incidence, i.
Refractive index (n) = sin i/ sin r
What is the unit for EMF?
Volt, V
Give an example of a transverse wave
Electromagnetic waves
Give an example of a longitudinal wave
Sound waves
What is the relative mass of a proton?
1
What is the relative mass of a neutron
1
What is the relative mass of an electron
0.0005
What is the nucleon number?
Aka the mass number, total number of protons and neutrons
What is the proton number?
Aka the atomic number, total number of protons in an atom
What are isotopes?
Atoms with the same number of protons but a different number of neutrons
What happens in alpha decay?
An alpha particle is emitted from the nucleus (made up of two protons and two neutrons)
Proton number goes down by two, nucleon number down by 4
What is beta decay?
A neutron in the nucleus turns into a protein and an electron. Electron is emitted from particle
Proton number goes up by 1, nucleon number doesn’t change
What is gamma decay?
High- energy electromagnetic radiation (gamma radiation) is emitted from nucleus
Number of protons and neutrons stay the same
What is the independent variable?
The thing you change in an experiment
What is the dependant variable?
The thing you are measuring in an experiment
What is a control variable?
Variables that must be kept the same to ensure it is a fair testament
What is a positive correlation
As one variable increases, the other increases
What is negative correlation
As one variable increases, the other decreases
