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Halloween Edition. EVERYTHING IS MOVING!!!. Linear Motion. Motion is Relative – there is no place in the universe that isn’t moving, so we must state motion “relative” to something else. Linear Motion.
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Halloween Edition EVERYTHING IS MOVING!!!
Linear Motion • Motion is Relative – there is no place in the universe that isn’t moving, so we must state motion “relative” to something else.
Linear Motion • Reference Frame – the spot designated “not moving”… all motion is described relative to it (usually the ground). Sometimes we will assign other places as reference frames. This changes the relative motion of ALL other objects.
Speed • A measure of distance covered in a time period, or how fast it is moving. S= d/t Ex. A car moves 60km in 3 hrs, it has a speed of 20km/hr distance
Speed S= d/t distance Which has a > speed? Why? Same distance < time
Speed: Types • Instantaneous Speed – how fast an object is moving at an “instant” of time. • Ex: Speedometer • Average Speed = total distance/ total time
Speed vs. velocity • V, velocity is a measure of distance covered in a time period, or how fast it is moving with a direction. V = d/t Ex. A witch that moves 60km North in 12 hrs has a velocity of: East South West North 5km/hr North
Δ (delta) means “change” Acceleration How many accelerators in the car??? Δ Velocity Δ time • Objects accelerate anytime their speed or direction changes.
Gravity! • Acceleration due to gravity (g) on Earth is about 10 m/s/s • REGARDLESS OF WEIGHT!!! What falls faster, a bowling ball or pebble?
Free Fall How Fast? How Far? Bluh, Bluh, Bluh, I Vant To Suck Your Bluuuud!
Velocity d t v t = d/v d = vt v = d/t
Acceleration Δv a Δt a = Δv/Δt Δv=aΔt Δt= Δv/a
Distance (free fall) d t2 ½ a d = ½ at2 a=2d/t2 t= √(d/½ a)
Equations (pg 1) • When velocity is constant: • V =d/t d=Vt t=d/V • When the object is accelerating: • a =ΔV/Δt ΔV =a Δt t= ΔV/a • d=1/2at2 Remember, gravity is an acceleration and can be substituted for a in any of the equations when gravity is doing the accelerating.
Distance Time Graphs Constant Velocity Graphed
Distance Time Graphs #2 Acceleration Graphed
Ideal Models and Air Resistance • Many examples will apply only in the “Ideal World” where air resistance/ friction doesn’t exist.
+10 m/s2 -10 m/s2 Speed & acceleration = Zero!
4 s 0m/s -10m/s/s 3 s 10m/s -10m/s/s 2 s 20m/s -10m/s/s 1 s 30m/s -10m/s/s 40m/s 0 s
4 s 0m/s +10m/s/s 5 s -10m/s +10m/s/s 6 s -20m/s +10m/s/s 7 s -30m/s Baseball ends up in his hand! +10m/s/s -40m/s 8 s
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