125 Physics Projects for the Evil Genius (75 page)

Project 19

  g = 2d/t
²

  a = 2d/t
²

Project 22

Project 31

Project 51

Project 56

Project 67

Project 68

Project 70

  f = v/2(L + 0.8d)

Project 77

  v = λf

  v = 331 + 0.6T

Project 81

Project 83

Project 85

  n
_i
sin (θ
_i
) = n
_r
sin (θ
_r
)

Project 86

  I/I
_o
= cos
²
θ

Project 96

  where
k
is the Coulomb constant = 9.0 × 10
⁹
m
²
/C
²

Project 100

  Ohm’s law

  V = RI

  R = VI, and

  I = V/R

  R
_series
= R
₁
+ R
₂

  1/R
_parallel
= 1/R
₁
+ 1/R
₂
+ …

Project 103

  The current for a charging capacitor is given by I = I
_o
e
^−t/RC

  The voltage for a charging capacitor is given by V = V
_o
(1 – e
^−t/RC
)

  The current for a discharging capacitor is given by I = I
_o
e
^−t/RC

  The voltage for a discharging capacitor is given by V = V
_o
e
^−t/RC

Project 116

  I = I
_o
e
^qV/kT

Project 121

  E
_photon
= hf

Project 125

1 m = 3.28 ft

1 mile = 1.61 km

1 inch = 2.54 cm

1 day = 86,400 s

1 year (365¼ days) = 3.16 × 10
⁷
s

1 J = 0.738 ft-lb = 0.239 cal

1 kW-hr = 3.6 × 10
⁶
J

1 W = 1 J/s

1 hp = 746 J

1 N = 0.225 lb

1 lb = 4.45 N

A 1 kg mass has a weight of 9.8 N (on Earth)

A 1 kg mass has a weight of 2.2 lbs (on Earth)

1 m/s = 2.24 mi/hr

1 km/hr = 0.621 mi/hr

1 km/hr = 0.278 m/s = 0.91 ft/s

1 cc = 1 cm
³
= 1 mL

1 liter (l) = 1000 cm
³

1 gal = 3.79 liters

1 Pa = 1 N/m
²
= 1.45 × 10
⁻⁴
lb/in
²

1 atm = 1.01 × 10
⁵
Pa

         = 14.7 lb / in
²
(psi)

         = 760 mm-Hg

         = 760 torr