Physik

Forces

• Balanced Force = Steady speed or at rest
• Unbalanced Force = acceleration/deceleration
• Either accelerate or
  change direction

  The more Mass an object has the more Force is needed for a change in direction.

Variables

• P = Momentum = kgm/s
• m = Mass = kg
• V = Velocity = m/s

Formula

• P = m * V
• m = P / V
• V = P / m

Mass in motion:
How many Kg's are put into otion devided by seconds.

What happens if you double the mass or velocity?

If you either double the mass or the velocity the momentum will also double.

Any change in momentum can be written as:

• Δp = m * Δv
• Δp = m * a * Δt
• Δp = m * a * Δt
• Δp = F * Δt

Impulse

• Change in momentum: Δp
• Overall effect of a force acting over time
• Symbol: J (N/s (Newton-seconds))
• Constant Force: J = F * Δt
• Net impulse: all forces on an object
• Net impulse formula: J_n = Δp = F_n Δt
•                                            ↳ p_f - p_i
•                                            ↳ m*v_f - m*v_i
• Beispiel:                             _{↳ (0,2kg)*(5m/s) - (0,2kg)*(-10m/s)}
•                                            = 1kg m/s - (-2kg m/s)
•                                            = 3kg m/s
• The minus sign is important, as momentum is a vector, there is a positive and negative direction.
• It has to be thought that there is a x and y direction, only 1 is calculated
• We can go back again:
• Net impulse formula: J_n = Δp = F_n Δt
•                                   3kg m/s = F_nx * (0,02s) 
•                                   F_n = (3kg m/s) / 0,02s = 150N 

_{Example: khanacademy.org}

Review

• v₁ = 20 m/s
• m₁ = 10kg
• Momentum: 20*10 = 200kgm/s
  
  
• v₂ = 10m/s
• m₂ = 20kg
• Momentum: 10*20 = 200kgm/s
  
  
• Total Momentum: 200 + 200 = 400kgm/s
• Drawing (before collision):
      _{20m/s          10m/s} 
• o-------->O ------->E
• If these 2 collide the momentum of the 2 balls must equal the momentum of the start
  
  
  
• After Collision:
    _{15m/s         ? m/s} 
• o------>O -------> E
• 150kgm/s + ? = 400kgm/s
• ? = 400kgm/s - 150kgm/s = 250kgm/s
• v = P/m = 250/20 = 12,5m/s
• Starting Energy is conserved

Force = ___kg * 9,82 = N

Work (Joules) = Force * distance

Power = Joules / t

The Physical action of applying or transferring energy arround in a system at different scales.

• movement
• pressure
• m*v
• momentum
• action and reaction
• machines
• acceleration
• chemical reaction
• wight → mass
• turning force
• impulse
• moments
• work
• power
• strength
• push and pull

Motion

↓ Momentum

Force

↓ Moments

Work

↓ Time & Work

Power

Piviot: point of turn. Example: Opening a coke with a piece of metal. Piviot is where the glass and the metal touches

The longer the piece the less Force is needed, but more distance is to overcome.