Our dynamic universe Flashcards
what are the equations of motion used for?
Acceleration
Projectile Motion
and any other movement question
F=ma is used when?
Unbalanced forces e.g. Friction, Air resistance
Tension
How do you calculate momentum?
p=mv
How to I find resultant forces?
Trigonometry (the hypotenuse is always the resultant force)
State Newtons 3 laws of motion?
- An object will remain at a constant velocity unless acted upon by an unbalanced force.
- The acceleration of an object is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
- Every action has an equal and opposite reaction
When do I use a vector diagram
Finding forces in two directions
Finding resultant force
Finding resultant speed
(You see a slope, think triangle)
What relationships can be used to calculate work done?
Ew =Fd
Ek = 1/2mv²
Ep=mgh
define impulse?
Change in momentum
Ft = mv − mu
What is frictional force?
the unbalanced force (the difference between the other two forces
How do I calculate impulse after a collision?
calculate momentum before & after collision
take away one value from the other
plug into Ft= mv - mu
What is Power
E/t
What is the difference between t and t’
t is proper time and t’ is time from the observers frame of reference
t < t’
Difference between l and l’
l is proper length, l’ is length from an observers frame of reference
l > l’
Calculate observed frequency
fₒ =fₛ (v/v+or-vₛ)
z=
redshift
Hₒ=
Hubble’s constant
p=
momentum
Area under displacement time graph
velocity
Area under velocity time graph
acceleration
what is terminal velocity
Maximum speed of an object, where all forces acting upon the object become equal
State the conservation of momentum
Momentum will remain the same before and after a collision provided that it isn’t acted upon by an unbalanced force.
inelastic and elastic
Inelastic is when external forces are acting upon the collision such as friction. Elastic collisions are free of any external forces.
Area under force time graph
impulse
speed of light in a vacuum
is the same for all observers
Causes shifts in the wavelengths of sound and light
the Doppler effect
moving away from us, longer wavelengths
Redshift
Moving towards us, shorter wavelengths
Blueshift
estimation of the mass of galaxies
dark matter
Accelerating expansion of the Universe
Dark energy
Peak wavelength shorter
Hotter object
Peak wavelength longer
Colder object
fs=
Source frequency
fo=
Observed frequency
Recessional velocity of a galaxy
V=Hod
