P2 Flashcards
Acceleration,
The rate at which velocity changes
Motion in a circle
Constant net force perpendicular to velocity
Speed
The distance an object travels per unit of time
Time
How long something takes
Calculating average speed
total distance/total time
Gradient equation
change in y/change in x
Acceleration equation
change in velocity/time taken
Kinetic energy equation (Joules)
0.5massspeed^2
Velocity time graphs
Shows how the speed or velocity of an object changes over time
Newton’s first law of motion
An object in motion will remain in motion unless acted upon by another force
Vector diagrams
The resultant vector for two vectors at right angles to each other can be worked out using a scale diagram, or using a calculation.
Newton’s Third Law
For every action there is an equal and opposite reaction
Momentum
The product of mass and velocity. It is also a vector quantity - this means it has both a magnitude and an associated direction.
Conservation of momentum
A ‘closed system’ is something that is not affected by external forces.
Work done equation
Force(N) * distance(M)
Power
The rate at which work is done
Elastic deformation
Can be reversed if the force is removed
Extension
When an object increases length
Compression
When an object decreases length
Elastic potential energy
The energy of stretched or compressed objects.
Gravity
A force of attraction between objects that is due to their masses.
Mass
The amount of matter in an object
Gravitational potential energy
When an object is lifted in a gravitational field, energy is transferred to a gravity store.
Scalar quantity
A quantity that can be described by magnitude only and has no direction
Vector quantity
A quantity that has both magnitude and direction
Velocity
Speed in a given direction
Distance
The length of a path between two points
Equation for Speed
distance/time
Distance time graphs
Shows how an object moves. The stationary line means distance does not change. When moving at a steady speed its a straight diagonal line (steeper means faster). If line slopes down, object is returning to starting position and slowing down.
Velocity equation
Velocity= change in position/time
Resultant forces,
Two forces can be added together to find it, also is a single force that has the same effect as two or more forces acting together.
Newton’s Second Law
Force = mass x acceleration
Terminal velocity
The constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity
Momentum equation
mass x velocity
Work done
When energy is transferred from one store to another and it is also done when a force causes an object to move.
Power equation
work/time
Plastic deformation
Can’t be fully reversed when the force is removed and their is a permanent change in shape.
Elastic limit
Maximum stress that a material will withstand without permanent deformation.
Force-extension graph
Linear extension and elastic deformation can be seen below the elastic limit. Non-linear extension and plastic deformation can be seen above the elastic limit. The gradient of a force-extension graph before the elastic limit is equal to the spring constant.
Energy stored in a spring
Work is done when a spring is extended or compressed.
Weight
A measure of the force of gravity on an object
Gravitational field strength
Where a mass experiences a force.
Gravitational potential energy equation
mass x gravitational field strength x height
What are non-contact forces?
A force produced because an object is in a field (two objects that don’t touch but create a force).
Name some examples of non-contact forces
Electrostatics, magnetism, gravity
How do you draw a freebody diagram?
Step 1: Identify all non-contact pairs
Step 2:Identify all contact pairs
Step 3: Focus on a single object. Draw that object with arrows showing all the forces acting on the object.
How do you resolve forces?
You can add up the two forces at a right angle.
