Equations Flashcards

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1
Q

What is the equation for thinking distance?

A

Thinking Distance = Reaction Time x Speed of the Car

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2
Q

What are the SUVAT equations?

A

v=u+at
s=ut+1/2at²
s=vt-1/2at²
s=1/2(u+v)t
v²=u²+2as

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3
Q

What equation relates force, mass and acceleration?

A

F = ma
Force (N) = Mass (kg) x Acceleration (ms-2)

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4
Q

How is the weight of an object calculated?

A

W = mg
Weight (N) = Mass (kg) x Gravitational force (ms-2)

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5
Q

How is the moment of a force determined?

A

M = Fd
Moment (Nm) = Force (N) x Perpendicular Distance of the Line of Action of Force from the Point of Rotation (m)

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6
Q

How is torque calculated?

A

T = Fx
Torque (Nm) = Perpendicular Separation Between Forces (m) x One of the Forces (N)

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7
Q

How is density calculated?

A

ρ = m/v
Density (kgm-3) = Mass (kg)/Volume (m3)

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8
Q

How is pressure calculated?

A

P = F/A
Pressure (Pa or Nm-2) = Force (N)/Area (m2)

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9
Q

What is the equation used to calculate the pressure exerted by a vertical column of liquid?

A

P = hρg
Pressure (Pa or Nm-2) = Height (m) x Density (kgm-3) x Acceleration by Free Fall (ms-2)

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10
Q

What is an expression for calculating upthrust?

A

U = vρg
Upthrust (N) = Volume of Liquid Displaced (m3) x Density of Liquid (kgm-3) x Acceleration due to Gravity (ms-2)

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11
Q

How is efficiency calculated?

A

Efficiency (%) = (useful output energy/total input energy) x 100

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12
Q

How is power defined as an equation?

A

P = E/t
Power (W) = Work Done (J)/Time (s)

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13
Q

What is an expression relating power and constant speed?

A

P = Fv
Power (W) = Force (N) x Constant Speed (ms-1)

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14
Q

How is gravitational potential energy calculated?

A

GPE = mgh
GPE (J) = Mass (kg) x Gravitational Field Strength x Change in Height (m)

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15
Q

How is kinetic energy calculated?

A

KE = 1/2mv²
KE (J) = 1/2 x Mass (kg) x Velocity² (ms-1)

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16
Q

What equation related force applied to a spring and its extension?

A

F = kx
Force (N) = Force Constant (Nm-1) x Extension (m)

17
Q

What are the two equations that can be used to calculate elastic potential energy?

A

E = 1/2Fx
E = 1/2kx²

F = force (N)
k = force constant (Nm-1)
x = extension (m)

18
Q

What is the equation for tensile stress?

A

σ = F/A
Stress (Pa) = Force (N)/Cross-sectional Area (m2)

19
Q

What is the equation for tensile strain?

A

ε = x/l
Tensile Strain = Extension (m)/Original Length (m)

20
Q

What is the equation for Young Modulus?

A

E = σ/ε
Young Modulus (Pa or Nm-2) = Tensile Stress (Pa or Nm-2)/Tensile Strain

21
Q

What equation defines electric current?

A

I = Q/t
Current (A) = Change in Charge (C)/Change in Time (s)

22
Q

What is the equation relating electric current and number density?

A

I = Anev

I - current (A)
A - cross sectional area (m2)
n - number density (m3)
e - elementary charge
v - drift velocity (ms-1)

23
Q

What is the equation for potential difference?

A

V = E/Q
Potential difference (V) = Energy Transferred (J)/Charge (C)

24
Q

What is the equation for electromotive force?

A

ϵ = E/Q
E.m.f (V) = Energy Transferred (J)/Charge (C)

25
Q

How is resistance defined?

A

R = V/I
Resistance (Ω) = P.d (V)/Current (A)

26
Q

What is the equation used to calculate resistance from length, cross-sectional area and resistivity?

A

R = ρl/A
Resistance (Ω) = (Resistivity (Ωm) x length (m))/Cross-sectional Area (m2)

27
Q

What are three equations that can calculate electrical power?

A

1) P=VI
2) P=I²R
3) P=V²/R

28
Q

How can the energy transferred by an electrical component in a given time be calculated?

A

E = VIt
Energy Transferred (J) = P.d (V) x Current (I) x Time (S)

29
Q

What are 4 key equations for analysing electrical circuits?

A

I=Q/t
V= W/Q
P = VI
V = IR

30
Q

What is the relationship between e.m.f, terminal p.d and lost volts?

A

E.m.f = terminal p.d + lost volts.

31
Q

What equation relates e.m.f, current, and internal resistance?

A

ϵ = I (R+r)
E.m.f = Current (Resistance + Internal Resistance)

32
Q

State the potential divider equation.

A

V(out) = [R₂/(R₁ + R₂)] x V(in)

33
Q

What is the wave equation?

A

v = fλ
Wave speed (ms-1) = Frequency (Hz) x Wavelength (m)

34
Q

How can phase difference be calculated for two points separated by distance x on a wave?

A

ΔΦ = d/λ
Phase Difference (degrees/radians) = Distance (m)/Wavelength (m)

35
Q

How is the intensity of a wave calculated?

A

I = W/A
Intensity (Wm-2) = Radiant Power Passing Through Surface (W)/Cross Sectional Area (m2)

36
Q

How is refractive index calculated?

A

n = c/v
Refractive Index = Speed of Light Through Vacuum (ms-1)/Speed of Light Through Material (ms-1)

37
Q

State the law of refraction.

A

nsinθ = k

n = refractive index
θ = angle between normal and incident ray.
k = constant