1D Elastic Collisions (4, 5)
Equations:
m1 m2
–
⋅
2 m1
--------------------- - v1i
⋅
v1f
=
--------------------- - v1i
⋅
v2f
=
m1
+
m2
m1
+
m2
Example:
Given: m1=10_kg, m2=25_kg, vli=100_m/s.
Solution: v1f=-42.8571_m/s, v2f=57.1429_m/s.
Drag Force (4, 6)
Equation:
2
ρ
⋅
v
⎛
⎞ A
⋅
- - - - - - - - - - - - -
⋅
F
=
C d
⎝
⎠
2
Example:
Given: Cd=.05, ρ =1000_kg/m^3, A=7.5E6_cm^2, v=35_m/s.
Solution: F=22968750_N.
Law of Gravitation (4, 7)
Equation:
⋅
m1 m2
⎛
⎞
⋅
------------------- -
F
=
G
⎝
⎠
2
r
Example:
Given: m1=2E15_kg, m2=2E18_kg, r=1000000_km.
Solution: F=266903.6_N.
Mass-Energy Relation (4, 8)
Equation:
2
⋅
E
=
m c
Example:
Given: m=9.1E-31_kg.
Solution: E=8.1787E-14_J.
5-24 Equation Reference