Motion in 1 and 2 dimensions
Physics Year 12 2016
By PresenterMedia.com
Newton’s First Law
Newton’s Second Law
Newton’s Third Law
The Law of Gravity
Conservation of Energy
Conservation of Momentum
The Force be With You – huh?
400Kg
1600kg
5400N
Sample 1.4 continued
The resultant force forward creates the acceleration
of the car and trailer
If there is a trailer attached, the trailer and car accelerate
individually at the same rate as the whole system
The resultant force on the trailer is composed of the force
forward from the car and the friction opposing its motion
The force on the car from the tow rope is the same as the
force on the trailer exerted by the rope
The Force be With You – huh?
The Force be With You – huh?
GRAPHS and FORMULAS
•
We describe motion using graphs
•
We use formulae to help make calculations easier
We write what we know on a diagram
We write down what we want to know
v = u + at
We choose the easiest formula
2
x
=
ut
+
½
at
We calculate the answer
2 = u2 + 2ax
v
We check that our answer makes sense
We check the units
•
•
•
•
•
•
Draw
Label
Calculate
KE = ½ m v2
PE = mgh
Conservation of Energy and Momentum
Momentum is conserved in all collisions BUT
IN ELASTIC COLLISIONS
•
Kinetic Energy is conserved and is
not considered to be “lost” as
sound, heat, or light
IN INELASTIC COLLISIONS
•
Kinetic Energy is not conserved
but is transformed into heat,
sound and /or light
Circular Motion
v
Is there any
acceleration?
v
v
v
Circular Motion
Velocity vector rotates by 2𝜋𝑉 in time T period
So acceleration, a = 2𝜋𝑉 /T
But V = 2𝜋𝑅/𝑇 where R is the radius of the circle
So a = ?
Or ???
Circular Motion
Billy Tea
http://www.youtube.com/watch?v=Hml7RVFULCA&feature=youtube_gdata_player
NASCARS
http://www.youtube.com/watch?v=yZa_S93bQWY&feature=youtube_gdata_player
Loop the Loop in a real car
http://www.youtube.com/watch?v=wiZoVAZGgsw&feature=youtube_gdata_player
Bike and Cars circular track
http://www.youtube.com/watch?v=hZOekFFSoWI&feature=youtube_gdata_player
vectors
http://www.youtube.com/watch?v=J0a6yoQ6ZRY&feature=youtube_gdata_player
Science theatre
http://www.youtube.com/watch?v=L6-kn2tB-9E&feature=youtube_gdata_player
https://phet.colorado.edu/en/simulation/rotation
https://www.youtube.com/watch?v=5ZnKIPfIhAQ
http://youtu.be/yAfg_8OLjvs Julius Sumner Miller
http://youtu.be/z3BSkMj1wLc
No such thing as centrifugal
accelerometer
https://www.youtube.com/watch?v=z79FZJyjPl8 for circular motion
http://www.physicsclassroom.com/Teacher-Toolkits/Circular-Motion/
Circular-Motion-Complete-ToolKit
Projectile Motion
http://www.youtube.com/watch?v=rMVBc8cE5GU&feature=related
https://phet.colorado.edu/sims/projectile-motion/projectile-motion_en.html
Scary stuff in Norway
https://www.youtube.com/watch?v=5ZnKIPfIhAQ