| What is the symbol for density | Weird p |
| What is the unit of the young modulous | Pascals
Nm^-2 |
| If a spring was held down with a mass attached to the bottom and attached to a firm surface at the other
Then let go to allow it to beoing up and down
What would be the spring potential
What would be the gravitational potential energy
What would be the kinetic energies of the spring
When the spring was at the very BOTTOM of its motion
And can you explain why | The potential energy of the spring is at a maximum since the spring is stretched at its maximum extension.
The potential energy due to gravity is at a minimum, since the mass is lifted the least amount above ground. In fact, if ground level is imagined at the bottom of the motion, the potential energy due to gravity is zero at this point of the motion.
The kinetic energy of the mass is zero, since the mass is temporarily stopped |
| Define density | Mass per unit volume |
| State hookes law | Force applied is directionally proportional to the extension, up to the limit of proportionality |
| State what the elastic limit is | Point at which a material will not return to its orinigal state |
| F = K x extension
What is k transcribing? | Stiffness |
| Define the tensile stress | Force over the area of a material |
| Whats the unit of tensile stress | Pascals |
| Whats the unit of tensile strain | Unitless |
| Whats is Elastic strain energy | Format in which energy is stored when work is done on a material to stretch or compress it |
| Define the breaking stress | Value at which the material will break apart |
| What is the area under a force-extension graph showing | Energy stored |
| Give a description of plastic behaviour | it does not return to its original shape and size when the force is removed |
| Whats plastic deformation? | Plastic deformation is the permanent change in a material’s shape when the stress applied to it by a force becomes too great |
| Give a description of brittle behaviour | likely to fracture (break apart) at a low extension |
| Give a descrtption of elastic behaviuor | An object is elastic when it comes back to its original size and shape when the load is no longer present |
| What would the force-extension graph of a brittle material look like? | s |
| What would the force-extension graph of a elastic material loook like | But linear gradient for longer |
| What would the force-extension graph of a plastic material look like | s |
| What would the force-extension graph of a very stiff material look like | p |
| If a force-extension graph does not return to its starting point what can be said about it | The material has been streched beyond its elastic limit
Material will not return back to its original shape and/ or size |
| What is the area between the loading and unloading parts of a stress-strain graph show | work done to permanently deform the material |
| Explain a plastic extension in terms of atoms and energy | Work is done to move atoms apart, so energy is not stored as elastic strain energy but is dissipated as heat |
| Define ductile | can undergo a large amount of plastic deformation before fracturing |
| Whats the tensile stress- strain graph of a ductile material look like? | -0 |
| Whats the tensile stress- strain graph of a plastic material look like? | 0 |
| Whats the tensile stress- strain graph of a brittle material look like? | 1 |
| If a spring was held down with a mass attached to the bottom and attached to a firm surface at the other
Then let go to allow it to beoing up and down
What would be the spring potential
What would be the gravitational potential energy
What would be the kinetic energies of the spring
When the spring was at the very top of its motion
And can you explain why | The spring is stretched the least, so, the potential energy of the spring is at a minimum.
The mass is lifted as high as it will go, so, the potential energy due to gravity is at a maximum.
The mass is stopped, so, its kinetic energy is zero |
| If a spring was held down with a mass attached to the bottom and attached to a firm surface at the other
Then let go to allow it to beoing up and down
What would be the spring potential
What would be the gravitational potential energy
What would be the kinetic energies of the spring
When the spring was at the middle of its motion
And can you explain why | Some energy is stored in the spring, since it is stretched to some degree; that is, there is some potential energy in the spring.
Some energy is stored in the gravitational field, since the object is lifted above ground; that is, there is some potential energy due to gravity.
The mass has reached its maximum speed; so, the kinetic energy of the mass is at a maximum |
