P5 Flashcards
Vectors
Quantities that have direction and magnitude
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 the gravity
Mass
The amount of ‘stuff’ in an object
Weight equation
Weight(N)=Mass(kg) x gravitational field strength(N/kg)
Earths 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 of an object. If it is equal to the objects 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
Running speed
3m/s
Cycling speed
6m/s
Car speed
25m/s
Train speed
55m/s
Plane speed
250m/s
Acceleration equation
Acceleration(m/s) = change in velocity (m/s) / time(s)
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
Fastest speed that an object can travel
Newton’s first law
If the resultant force on a stationary object is 0. The object will remain stationary
Newton’s second law
Acceleration is proportional to the resultant force
Resultant force equation
Resultant force(N) = Mass (kg) x acceleration(m/s)
Newtons 3rd law
When two objects interact, the forces they exert on each other are equal and opposite
Inertia
The tendency for the motion to remain unchanged
Stopping distance equation
Stopping distance = thinking distance + braking 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)
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)
