Kinematics
S = So + VoT + 0.5ATT
V = Vo + AT
S = Position at time "T" So = Position at time ZERO
V = Velocity at time "T" Vo = Velocity at time ZERO
A = Acceleration (MUST BE CONSTANT)
T = time since the start (start time is ZERO)
Example:
How far will a mass move if it is going 10 m/sec and is accelerated
at 4 m/sec.sq for 5 sec.
S = So + Vo ( t ) + 1/2 ( A )( t )( t)
= 0 + 10 ( 5 ) + 1/2 ( 4 )( 5 )( 5) Note: starting distance is
zero
= 0 + 50 + 2 ( 25 )
= 0 + 50 + 50
= 100 meters
How fast will a mass be moving if it is going 10 m/sec and is
accelerated at 4 m/sec.sq for 5 sec.
V = Vo + A ( t)
= 10 + 4 ( 5 )
= 10 + 20
= 30 m/sec.
F = MA
F = Force M = Mass
A = Acceleration (MUST BE CONSTANT)
Work and energy
Kinetic Energy Ek = .5mVV (one half Mass times velocity squared)
Gravitational Energy Eg = mgh (On earth g = 9.81 but we use 10)
Work = Force x Distance
h = Height m = mass V = speed (or Velocity)
Example:
A mass of 5 kilograms is moving at 10 m/sec. at a height of 8 meters.
A) What is its Kinetic Energy?
Kinetic energy = 1/2 X mass X Velocity X Velocity
= 1/2 X 5 X 10 X 10
= 1/2 X 5 X 100
= 1/2 X 500
= 250 joules
What is its Potential energy?
Gravitational energy is the only potential energy in the problem
Gravitational Energy = mass X Gravity X Height
= 5 X 10 X 8
= 5 X 80
= 400 joules
What is the total energy?
The Total means ADD ALL THE ENERGY
250 + 400 = 650 joules
