Predictions for this year's Unit 3 Exam

[Cinnah]

it's a 90 degrees - the total angle of the normal to the surface is always 90, so the space between the dotted parallel line and the normal line is going to be 90-theta. If you'd ever need that information :/

[Bozo]

Ok, guys, I only have a few questions before my knowledge of the course is more or less 100% complete.

How do I find design angle etc for a banked curve when friction is acting as well as a component of the normal reaction force? In past papers students have more or less hacked banked curves with the tan formula etc and I have a strong feeling this year they will test us on this...

When an input signal is given and it is not correctly biased with respect to the vout-vin characteristic. Do we bias it about the quiescent point or do we sketch the output signal as just being massively distorted?

Do photodiodes with incident light actually produce current or simply allow more current to pass through?

Thank you everybody!!!!!!

Can someone answer this

[xZero]

General formula for banked curve with friction. Fnet=Fc+Fcos(theta), F  = friction and it can be positive or negative depending on the question. Fc=Centripetal force and Fnet=mv^2/r.

[jinny1]

General formula for banked curve with friction. Fnet=Fc+Fcos(theta), F  = friction and it can be positive or negative depending on the question. Fc=Centripetal force and Fnet=mv^2/r.

So you are saying mv^2/r= mv^2/r + Fcos(theta)

[xZero]

Fc=mgtan(theta), it only equals to mv^2/r if friction is not presented

[Bozo]

With regards to structures and materials. What can i obtain from the FORCE vs extension graphs.

[DisaFear]

With regards to structures and materials. What can i obtain from the FORCE vs extension graphs.

During elastic behaviour, the force vs extension/compression graph is a straight line through the origin
The stiffness is the gradient of the force versus compression/extension graph
Force applied to a material equals stiffness times the extension

That's all I could find
What would the area be? EPE?

[Bozo]

+1 on that what would be the SPE

[Asx4Life]

The best way to look at banked curves is to draw a diagram with all the forces acting on an object then resolving it into horizontal and vertical components. Then you can derive you own formula's and test it out. That way, you can understand how the formula's work.
Anyone done chemology 2011? Most ridiculous paper i've done so far =(

[adelaide.emily10]

Fc=mgtan(theta), it only equals to mv^2/r if friction is not presented

ok so i am tad confused. if we're trying to find the angle of a banked curve with friction then we can use
mgtan(theta)=mv^2/r+FrCos(theta) and transpose etc. ?

btw the area under a force vs extension graph for structures and materials is the work done i.e strain energy (do NOT need to multiply by volume for this energy)

[pi]

With regards to structures and materials. What can i obtain from the FORCE vs extension graphs.

During elastic behaviour, the force vs extension/compression graph is a straight line through the origin
The stiffness is the gradient of the force versus compression/extension graph
Force applied to a material equals stiffness times the extension

That's all I could find
What would the area be? EPE?

Area, elastic potential energy per unit volume

Area is work


EDIT: MY BAD, didn't read properly!

[xZero]

Fc=mgtan(theta), it only equals to mv^2/r if friction is not presented

ok so i am tad confused. if we're trying to find the angle of a banked curve with friction then we can use
mgtan(theta)=mv^2/r+FrCos(theta) and transpose etc. ?

btw the area under a force vs extension graph for structures and materials is the work done i.e strain energy (do NOT need to multiply by volume for this energy)

okay mv^2/r = mgtan(theta)+FrCos(theta), to find theta just do some transposing

[adelaide.emily10]

Area, elastic potential energy per unit volume

Are you sure its per unit volume? because i thought it was just strain enrgy and the area under a stress vs strain graph is strain energy per unit volume?

[Bozo]

With regards to structures and materials. What can i obtain from the FORCE vs extension graphs.

During elastic behaviour, the force vs extension/compression graph is a straight line through the origin
The stiffness is the gradient of the force versus compression/extension graph
Force applied to a material equals stiffness times the extension

That's all I could find
What would the area be? EPE?

Area, elastic potential energy per unit volume

Isn't that for a stress vs strain graph.

we are talking about force vs extension graphs.

[pi]

Yep, sorry, my bad. post fixed. didn't read properly



Area is actually work or change in energy.