physics Flashcards
(18 cards)
1
Q
what is velocity
A
- rate of change of displacement (ms-1)
2
Q
what is acceleration
A
- measure of how quickly velocity changes (ms-2)
3
Q
what is projectile motion
A
- a parabolic path traveled by an object projected into the air
- the object’s motion is influenced by; initial launch speed, launch angle and acceleration due to gravity
4
Q
what is centripetal motion / force
A
- M: motion in a circular path due to the action of centripetal force
- F: force on an object directed to the centre of a circular path that keeps the object on the path
5
Q
what are newtons three laws of motion
A
- an object will continue in a state of inertia unless acted upon by an unbalanced external force
- acceleration of an object is directly proportional to the net force acting on it and inversely proportional to the mass (F = (m)(a)
- every force has an equal and opposite reaction force
6
Q
what is universal gravitation
A
- every object exerts a gravitational force on every other object
- force = directly proportional to mass (increase mass = increase force)
- force = inversely proportional to distance (increase distance = decrease force)
- distance has more of an impact than weight
- F = Gm1m2 / r^2
7
Q
what is kinetic energy vs potential energy
A
- K: mechanical energy, object in motion, how quickly its moving
- P: mechanical energy, potential to do work, 0 at ground
8
Q
what is archimedes principle
A
- the buoyant force acting on a substance in a fluid at rest is equal to the weight of the fluid displaced by the substance
9
Q
what is the combined gas law
A
- under constant temperature (in kelvins = celsius +273), pressure and volume are constant
- as pressure increases the volume decreases
- P1V1 / T1 = P2V2 / T2
10
Q
what is the law of conservation of electric charge
A
- net amount of electric charge produced is always zero, net electric charge can not be created or destroyed
11
Q
what is coloumb’s law
A
- interaction between electrically charged objects
- like charges repel and opposite charges attract
- repel / attract proportional to the charge
12
Q
what is a parallel vs series circuit
A
- P: two or more resistors connected across two points, Req = 1/R1 + 1/R2 + 1/R3, parallel lines in-between, current = changes (I = I1 + I1 + I3), same voltage, I increases = R decreases
- S: two or more resistors connected one after the other, Req = R1 + R2 + R3, circle, current = same, differing voltages (V = V1 + V2 + V3)
13
Q
what is wavelength, amplitude and frequency and how are they related
A
- λ: wavelength, metres, between peak of one wave and corresponding peak of another or two corresponding points
- a: maximum height of a crest / trough relative to normal level
- f: number of oscillations passing a given point per second (number of crests)
- v (speed) = (f)(λ)
14
Q
what is reflection
A
- wave hits an object and bounces off of it
- beam striking surface will reflect with an angle equal to that of the incident beam
- diffuse reflection: rough surface, different directions of reflection
- perfect reflection: incident angle = reflected angle
- total internal reflection: angle of incidence exceeds the critical angle
15
Q
what is refraction
A
- deflection of a wave passing from one medium (air) into another (glass), light bends towards normal
- change in medium / speed (refractive index)
- incident ray angle (between ray and normal)
- refracted ray angle (between ray and normal)
- critical angle: angle of incidence gives an angle of refraction of 90° [sin𝜃c = (n2 / n1)sin90]
16
Q
what is snells law
A
- relationship between angles of incidence (Li) and refraction (Lr)
- n1sin𝜃1 = n2sin𝜃2
- n1 (reflection index of first material), 𝜃1 (angle of insert), n2 (refraction index of second material), 𝜃2 (refraction angle)
17
Q
what is transverse / longitudinal wave:
A
- t: particles of medium vibrate up and down in direction perpendicular to that of travel
- l: vibration of particles along the direction of the waves motion
18
Q
what are vector and scalar quantities
A
- V: displacement (m), weight (N), velocity (ms-1), acceleration (ms-2), angle (horizontal / vertical), momentum (P)
- S: distance (m), mass (kg), time (s)
