P5 Flashcards
Vectors
Quantities that have a magnitude and direction
Scalars
Quantities that only have a magnitude
Vector Examples
Force, velocity, displacement, acceleration, momentum
Scalar Examples
Speed, distance, mass, temperature, time
Contact Forces
A force that requires 2 objects to be touching
Non-Contact Forces
A force that does not require 2 objects to be touching
Contact Force Examples
Friction, air resistance, tension
Non-Contact Force Examples
Magnetism, gravity, electrostatic forces
Weight
The force acting on an object due to gravity
Mass
The amount of ‘stuff’ in an object
Weight Equation
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
Earth’s Gravitational Field Strength
9.8N/kg
Resultant Force
The overall force on a point or object
Extension Equation
Force (N) = Spring Constant (N/m) x Extension (m)
Moment Equation
Moment (Nm) = Force (N) x Distance (m)
Moment
The turning effect of a force
Pressure Equation
Pressure (Pa) = Force (N) / Area (m)
Pressure Of A Liquid Equation
Pressure (Pa) = Height (m) x Density (kg/m) x Field strength (N/kg)
Upthrust
Force on an object. If it is equal to the object’s weight, it will float. If the upthrust is less than the weight, it will sink
Floating
Depends on the density of the solid compared to the density of the liquid
Atmospheric Pressure
Created on a surface by air molecules. Decreases with height
Distance
How far an object has moved. It is a scalar quantity
Displacement
Vector quantity. Measures distance and direction in a straight line from A to B
Walking Speed
1.5m/s
Acceleration Equation
Acceleration (m/s) = Change in velocity (m/s) / Time (s)
Uniform Acceleration Equation
2 x Acceleration x Distance = Final velocity^2 - Initial velocity^2
Distance Time Graph Gradient
Tells you the speed
Velocity Time Graph Gradient
Tells you the acceleration
Friction
Force between 2 surfaces in contact. Acts in the opposite direction to movement
Drag
Resistance in air or fluid
Terminal Velocity
The fastest speed that an object can travel. Happens when friction and acceleration forces are equal
Newton’s First Law
If the resultant force on a stationary object is zero, the object will remain stationary. If the resultant force on a moving object is zero, it’ll carry on moving at the same velocity
Newton’s Second Law
Acceleration is proportional to the resultant force
Resultant Force Equation
Resultant Force (N) = Mass (kg) x Acceleration (m/s)
Newton’s Third Law
When two objects interact, the forces they exert on each other are equal and opposite
Inertia
The tendency for motion to remain unchanged
Stopping Distance Equation
Stopping Distance = Thinking Distance + Breaking Distance
Thinking Distance Factors
Speed, reaction time, alcohol, drugs
Breaking Distance Factors
Speed, weather, tyre condition, brake quality
Momentum Equation
Momentum (kg m/s) = Mass (kg) x Velocity (m/s)
50mph Distances
Thinking = 15m, Breaking = 38m
Momentum
How much ‘oomph’ an object has. In a close system it is always conserved
Change In Momentum Equation
Force (N) = Change in momentum (kg m/s) / Change in time (s)
Crumple Zone
Area on a car designed to crumple, increasing the time it takes the car to stop
Seat Belts
Stretchy meaning that it takes longer for the wearer to stop in the event of an accident
Air Bags
Initiate before you hit the dashboard of a car. Slows you down gradually
