# Mechanics

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• Created by: Alex
• Created on: 23-02-14 09:57
• Mechanics
• Constant Acceleration Equations
• SUVAT
• v = u + at
• s = ut + 1/2 at^2
• s = 1/2 (u + v)t
• v^2 = u^2 + 2as
• s = vt - 1/2 at^2
• Acceleration due to gravity is when a = g
• g = 9.8 m/s^2
• up? a = g      down a = -g
• Motion Graphs
• Displacement Time
• the maximum displacement is the highest point on the graph.
• Velocity Time
• Area = Distance
• Displacement, Velocity and Acceleration
• displacement  --> velocity --> acceleration    differentiate!
• Acceleration --> velocity --> displacement integrate!
• Vectors
• vectors have magnitude and direction, scalars only have size.
• scalars
• speed, distance
• velocity, displacement, accceleration and force.
• the length of the arrow shows the magnitude of the vectore
• Forces and Modelling
• weight = mg
• Reaction is 90 degrees to the surface
• Friction opposes motion
• Tension opposes weight
• The 'model' is the forces diagram
• Forces and Vectors
• forces have components
• Horisontal = Fcos*
• Vertical = Fsin*
• R^2 = a^2 + b^2
• Friction
• F is less than or equal to the fristion force.
• Limiting friction is when F = mew R
• Newtons Laws
• A body will stay at rest unless a resultant force acts on it.
• The overall resultant force is equal to mass x acceleration
• For each force has an equal and oposite reaction force
• Friction and inclined planees
• Use F = ma in 2 directions in inclined plane questions.
• Resolve forces parallel and perpendicular
• Connected Particles
• Think friction!
• Momentum
• Momentum = mass x velocity
• Ft = mv - mu
• momentum before = momentum after
• Masses joined together have the same velocity