Physics Exam Review Flashcards
What are the rules for significant digits?
If there is a decimal point leading 0s are insignificant
If there isn’t a decimal 0s to the right are insignificant
All other digits are significant
What are the rules for significant digits when multiplying and dividing ?
Round your final answer to the least # of significant fig
What are the rules for significant digits when adding and subtracting?
Round the final answer to the least accurate # of decimal places.
What is a scalar quantity?
Has magnitude but no direction
What is a vector quantity?
Has magnitude and direction
How do you add vectors in 2 dimensions?
Option 1: Scale diagram. Option 2: Trig.
How do you find the average speed/ velocity?
Speed= distance/time. Velocity= displacement/time.
How to find instantaneous velocity?
Use the slope. M= change in y/change in x
What is mass?
The quantity of matter in an object
What is weight?
The force of gravity on an object.
What is inertia?
The property of matter that resists change to its motion. The greater the mass the greater the inertia.
What is Newton’s first law?
If the net force is 0 it will remain at rest or remain in motion at a constant velocity.
What is newton’s 2nd law?
If the net external force is not 0 the object will accelerate in the direction of the net force.
What is Newton’s 3rd law?
For every action force there is a reactionary force of = magnitude and opposite direction.
What is static friction?
Acts on a stationary object and prevents motion.
What is kinetic friction?
Acts to oppose the motion of a moving object.
What is the coefficient of friction?
The ratio of the magnitude force of friction to the magnitude of the normal force.
What is work?
Is the energy transferred to an object by applied force for a measured distance. J=Nm
What is mechanical energy?
The sum of the Eg and Ek for an object.
What is percent efficiency?
The ratio of useful output to total energy input.
What is power?
The rate work is done or energy is transferred. 1J/s=1W
What is transverse vibration?
Object vibrates perpendicular to its axis. (swing)
What is longitudinal vibration?
Object vibrates parallel to the axis. (baby jumper)
What is torsional vibration?
Twists back and forth around its axis.
What is Amplitude?
(A) Distance from equilibrium position to max displacement
What is Frequency?
(f) # of cycles completed per unit time. f= #cyc/total t
What is Period?
(T) Time to complete one full cycle. T= total t/#cyc
State the principle of Superposition
At any point in the medium the resulting amplitude is the algebraic sum of the two interfering amplitudes.
What does a reflected pulse from a free end look like?
reflected
What does a reflected pulse from a fixed end look like?
reflected and inverted
Define Wave
A periodic disturbance which transfers energy over a distance
What are the characteristics of a wave?
Crest: The region where the displacement is positive
Trough: The region where the displacement is negative
Amplitude (A): The distance above/below its equilibrium position to max displacement
Wavelength (λ): The distance between any consecutive points on the waves which are in phase (crest-crest)
Does amplitude of a pulse affect its speed?
No
What happens to wavelength if frequency of vibrations is increased?
As frequency increases, wavelength decreases.
Doppler effect
Moving towards = shorter λ, (Vw/Vw-Vs), fd > fs
Moving away = longer λ, (Vw/Vw+Vs), fd
Vw-speed of wave, V/f s-source speed/frequency
Resonance in open air columns
and closed air columns
O: 1st resonant length = 1/2λ, 2nd = 1λ, 3rd = 3/2λ
C: 1st resonant length = 1/4λ, 2nd r.l. = 3/4λ, 3rd r.l. = 5/4λ
What would happen to the force experienced by two objects if one mass was doubled?
The force would double.
What would happen to the force experienced by two objects if both masses were doubled?
Force would be 4x as big.
What would happen to the force experienced by two objects if the distance between them was doubled?
Force would be 1/4 as big
What would happen to the force experienced by two objects if the distance between was halved?
Force would be 4x as big
What is Specific Latent Heat of Fusion?
Amount of therm energy required to melt
Lf=Qf/m
What is Specific Latent Heat of Vaporization?
Amount of therm energy required to vaporize (per kg) of a substance at boiling point
Specific Latent Heat Equation for Q?
Q(f/v) = mL(f/v)
Transverse Waves
When particles vibrate perpendicular to the direction of the wave
Longitudinal Waves
Particles vibrate parallel to the direction of propagation of the wave. Extensions are rarefactions, and compressions…
Force of attraction between charges
Fe = kQ1Q2 / d^2
Find charge if deficit/excess
q = ne
What is Induced Fission?
Nucleus struck with free neutron becomes unstable and splits
What is Spontaneous Fission?
Unstable heavy isotope splits without interaction
What is an atomic mass unit (amu)?
1/12th the mass of carbon-12 mucleus
Alpha Particle
Helium nucleus
What is Proper Nuclear Notation?
Atomic# on bottom, total# of particles in nucleus on top
How to find speed of sound?
v=331.6+0.606t
Half life finding t or h
find a common base or log
Position Time Graphs
Shows distance over time with respect to reference point. To find velocity use slope. To find acceleration use tangent method.
Velocity Time Graphs
Shows velocity over time. To find displacement use area under graph. To find acceleration use slope.
