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Forces and Motion - Coggle Diagram
Forces and Motion
Exam Questions
Distance vs displacement
Speed vs velocity
Calculate speed
Calculate acceleration
Interpret motion graphs
Calculate distance from velocity-time graph
Explain terminal velocity
Apply Newton's First Law
Use F = ma
Describe Newton's Third Law pairs
Newton's Second Law
Acceleration proportional to force
Acceleration inversely proportional to mass
Equation
F = ma
Force
Newtons (N)
Mass
Kilograms (kg)
Acceleration
m/s²
Rearrangements
a = F ÷ m
m = F ÷ a
Typical Speeds
Walking
1.5 m/s
Running
3 m/s
Cycling
6 m/s
Car
25 m/s
Train
30 m/s
Plane
250 m/s
Newton's First Law
Resultant Force = 0
Object remains stationary
Or
Object continues at constant velocity
Forces balanced
Non-zero Resultant Force
Causes acceleration
Acceleration
Definition
Rate of change of velocity
Equation
Acceleration = Change in Velocity ÷ Time
a = Δv ÷ t
Units
m/s²
Positive Acceleration
Speeding up
Negative Acceleration
Slowing down
Deceleration
Terminal Velocity
Falling Objects
Weight acts downwards
Air resistance acts upwards
At Start
Weight > Drag
Object accelerates
As Speed Increases
Drag increases
Acceleration decreases
Terminal Velocity
Drag = Weight
Resultant force = 0
Constant velocity
Parachutists
Parachute closed
Higher terminal velocity
Parachute open
Greater drag
Lower terminal velocity
Friction and Drag
Friction
Acts opposite to motion
Slows objects down
Drag
Fluid resistance
Acts in liquids and gases
Air Resistance
Type of drag
Increasing Speed
Increases drag force
Inertia
Tendency to resist changes in motion
Object at rest
Stays at rest
Object moving
Continues moving
Greater Mass
Greater inertia
Distance and Displacement
Distance
Scalar quantity
Total path travelled
No direction
Displacement
Vector quantity
Distance in a straight line
Includes direction
Example
Travel 5 m north then 5 m south
Distance = 10 m
Displacement = 0 m
Speed and Velocity
Speed
Scalar quantity
How fast an object moves
Velocity
Vector quantity
Speed in a given direction
Changing Velocity
Change in speed
Change in direction
Or both
Average Speed
Total distance travelled
÷
Total time taken
Uniform Acceleration
Constant acceleration
Equation
v² - u² = 2as
Variables
v
Final velocity
u
Initial velocity
a
Acceleration
s
Distance travelled
Newton's Third Law
Forces occur in pairs
Action and Reaction Forces
Equal magnitude
Opposite direction
Act on different objects
Examples
Walking
Rocket launch
Pushing against wall
Speed Equation
Speed = Distance ÷ Time
Equation
v = s ÷ t
Motion Graphs
Distance-Time Graphs
Gradient
Speed
Horizontal Line
Stationary
Straight Slope
Constant speed
Steeper Gradient
Faster speed
Curved Line
Changing speed
Velocity-Time Graphs
Gradient
Acceleration
Horizontal Line
Constant velocity
Upward Slope
Positive acceleration
Downward Slope
Negative acceleration
Steeper Gradient
Greater acceleration
Area Under Graph
Distance travelled
Inertial Mass
Measure of how difficult it is to change velocity
Equation
Inertial Mass = Force ÷ Acceleration