P2.3 Flashcards
What are plastic materials
Materials that stretch but don’t return to their original shape they are deformed when you apply forces and stay that way when u remove them.
What are elastic materials
Return to their original shape when you remove the forces
What is an elastic material shown as on a graph
A straight line
What is the limit of proportionality
The point where the graph of force against extension is no longer straight and then curved.
What is the elastic limit
The point where it stops behaving elastic and after this point won’t return to it’s original shape.
Equation for force exerted by a spring
Force exerted by a spring = spring constant x extension
What is the gradient of the force extension graph
The spring constant
When is force and extension proportional
Up to the limit of proportionality
Formula for extension
extension = final length - original length
equation for energy transferred by the spring
energy transferred in stretching = 1/2 x spring constant x extension squared
What is a gravitational field
A region where a mass experiences an attractive force
Formula for gravity force
gravity force = mass x gravitational field strength
What is gravitational field strength
A measure of the force on 1kg of mass when it is in the gravitational field of another mass
Weight formula
Weight = mass x gravitational field strength
what is the acceleration due to gravity
10 m/s squared
Formula for gravitational potential energy
gravitational potential energy = mass x height x gravitational field strength
What is a moment
A turning effect
What does a moment depend upon
It depends on the size of the force and the distance from the pivot where the force acts, where the direction of the force and the distance measures are at 90 degrees to eachother
Moment formula
Moment = force x distance
When is an object balanced
An object is balanced when the anticlockwise moments = the clockwise moments
What is a lever
A lever is a force multiplier as it transmits force by rotating around a pivot
What is the effort
the force exerted on the lever
What is the load
the force the lever exerts on the load
mechanical advantage formula
mechanical advantage = load/effort
Formula for force output
effort x distance from pivot to effort = load x distance from load to pivot
What does the ratios of cogs tell you
The ratio of diameters of the cogs gives you the force multiplication of it
What is essential for hydraulics
Pressure is conserved in liquids
When a larger cog feeds into a smaller cog what happens
speed multiplication
