# P5: Space for Reflection

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• Created by: Theex
• Created on: 23-04-14 15:53
• P5: Space for Reflection
• Vectors and equations of motion
• Left -> right is +
• Right -> Left is -
• What the arrow shows about the vector quantity
• Direction of arrow shows direction of vector quantity
• Length of arrow shows size of vector quantity
• Relative motion - how fast an object appears to be moving compared to you.
• V of 'a' relative to 'b' = Va - Vb
• To resolve vectors acting at 90 use pythagoras theorem
• Equations of Motion
• These equations can describe the motion of almost any object using maths
• suvat
• s = distance travelled (m)
• u = initial velocity (m/s)
• v = final velocity (m/s)
• a = acceleration (m/s^2)
• t = time taken (s)
• Equations
• v = u + at
• s = ut + (1/2)(a)(t^2)
• v^2 = u^2 + 2as
• s = ((u + v)/2)t
• Projectile motion
• Mr Hays' quote: "Gravity doesn't take a holiday just because an object is moving
• Gravity = 9.81ms^-2
• What equations to use?
• Vertical Plane: suvat
• Equations
• v = u + at
• s = ut + (1/2)(a)(t^2)
• v^2 = u^2 + 2as
• s = ((u + v)/2)t
• suvat
• s = distance travelled (m)
• u = initial velocity (m/s)
• v = final velocity (m/s)
• a = acceleration (m/s^2)
• t = time taken (s)
• Horizontal plane...
• v = s / t
• Time is the only value shared across both planes
• What equations to use?
• Vertical Plane: suvat
• Horizontal plane...
• v = s / t
• Action and reaction
• Newton's Third Law: "When an object collides or two bodies interact, the two objects exert an equal and opposite force on each other."
• F = m * a
• When t * 2, a * 1/2 because...
• a = V / t
• And when a * 1/2 so is F because...
• F = m * a
• Momentum
• Momentum is conserved
• Coalesce - When two objects moving in the same direction collide and stick together their momentum is then shared
• (m1 * u1) + (m2 * u2) = (m1 + m2)Vf
• p = m * v