Physics+and+the+Car

= Physics and the Car = Timeline for this unit:

Vectors 1


//Science of Physics//

Task1. SpeedQuiz: Task 2: Build your dream car
 * Design a car.
 * Explain the performance advantages / properties of your design.
 * Explain these using physics terms. What measures are being used?
 * How are they measured?
 * Compare the properties of other models / components.
 * Keep this design for further analysis later in the unit.

Vectors 2:
//Science of speed//

Speed:

 * measurement, formulas, graphing motion.
 * How can you measure speed?
 * What methods are there?
 * What issues are there in taking these measurements? *

Research speed:
 * fastest car (record, design, conditions) *

Dist/time/speed graphs:
 * complete together.
 * [[file:Distance time and speed time graphs.doc]]

Prac 1: speed >
 * Graph motion.
 * write up, including research from this and previous lesson
 * [[file:Prac template keynote.key]]
 * [[file:Speed prac.xls]]
 * [[file:Speed prac.xls]]


 * Analyse graphs.
 * Introduce the idea of vectors (force and direction)

Vectors 3
//Science of Braking//



__Momentum and Braking__:
 * Momentum is the product of an object's [|mass] and [|velocity]. It is a [|vector].
 * The SI units of momentum are kg * m/s.
 * p=mv (p=momentum, m=mass, v=velocity)
 * Applications of momentum:
 * Sport... Transport... Where else?




 * A Fielder Moving his Hands Backward WhileTrying to Catch a Ball
 * An athlete before jumping runs some distance because this forward momentum may help him to jump high.


 * Read Ch8 p171-172… Speed and stopping distance.
 * Copy these notes: Using road accident data, scientists at the University of Adelaide assessed the risk of being killed or injured in a car crash at different speeds. They found that every 5 km/h over 60 km/h doubled a person’s risk of being involved in a crash.




 * Visit the [|TAC “wipe off 5”] website.
 * Copy the reasons why higher speed reduces safety and its effect on crashes.

Pracs!!
For the following pracs work in groups of three. Write up both pracs as you are doing them. Include the formula for momentum and stopping distance. Answer the questions from the textbook (p171-2) and by visiting the websites below. Submit at end of following period. Don't forget to attempt the self grading at the end.

Prac 1: Braking distance p171


[|NRMA website].
 * 1) Compare the stopping distances for old and new cars.
 * 2) According to the NRMA what is the key factor in speed related crashes?

Prac 2: driving distractions. p172


[|California Dept of Motor Vehicles]
 * 1) Identify 5 distractions that you have witnessed that are listed on this website
 * 2) How do distractions affect reaction time?
 * 3) What effect would tiredness have?
 * 4) What affect does alcohol have? (and when does this affect start?)

Extra reading for discussion
 * [|Prison term for speeding]
 * [|Mentally teens drive best alone]



= Tyre Safety = Tyre safety 10 min: ABC (USA) News Report [|Tyre safety information] (UK) - award winning site



Inflation
__Correct tyre pressure__
 * //Correct pressures are related to loads, speeds and vehicle handling and are vital for maximum safety, braking, grip and good tyre life.//
 * //To find the correct tyre pressures look for your// car’s tyre placard //. That's the small information sticker on the door jamb, under the sun visor or on the inside of the glove box lid. It shows the correct tyre size and pressures for your car. The owner’s handbook may also be of assistance, either with the location of the tyre placard or a table with the specified tyre pressures.//
 * //Inflation pressure should be checked at least// every two weeks //and only when the tyre is cold, since there is an increase in pressure when the tyre has warmed up after being run.//

__Underinflation__: __Overinflation__
 * //Prolonged under-inflation causes excessive flexing, deterioration of the casing and rapid wear of the tread shoulders. The vehicle will also consume more fuel.//
 * //Over-inflation results in an uncomfortable ride, a reduced area of contact with the road, accelerated wear on the tread centre and makes the tyre more susceptible to impact damage.//



Minimum tread

 * Tyre treads are designed to give good grip on wet roads, but in general wet grip decreases as tyre tread pattern wears down or as the depth of water increases. Motorists should take this into consideration and reduce speed when it is wet. The legal minimum tread depth is 1.6mm throughout a continuous band comprising the central three-quarters of the breadth of tread and round the entire outer circumference of the tyre. However tyre wet grip deteriorates more rapidly in the second half of its tread life and wet stopping distances can dramatically lengthen. It is therefore advisable consideration is given to replacing tyres well before they reach the legal minimum

Tyre Age

 * The chronological age of any tyre can be found on the tyre sidewall by examining the characters following the symbol "DOT".
 * For tyres manufactured after the year 1999, the last four numbers identify the date of manufacture of the tyre to the nearest week. The first two of these four numbers identify the week of manufacture (which range from "01" to "52"). The last two numbers identify the year of manufacture (e.g., a tyre with the information " DOT XXXXXX2703” was manufactured in the 27th week of 2003 ).
 * For tyres manufactured prior to the year 2000, three numbers instead of four indicate the date of manufacture. Also, during the early 1990’s, a triangle was added to the end of the character string to distinguish a tyre built in the 1990’s from previous decades (e.g., a tyre with the information "DOT XXXXXX274 was manufactured in the 27th week of 1994).

media type="custom" key="7425947" align="center"

Tyre safety report on teacher's cars

 * Investigate the tread of the tyres on the cars in the teachers’ car park. Are there any cars that have unsafe tyres? Write a report to the car owner explaining why they should get new tyres and give the report to them
 * tyre age
 * inflation
 * under / over
 * tyre tread depth
 * tyre condition
 * cuts, cracks, bulges, flat spots, scuffing on side walls (curb impact)
 * irregular wear (wheel alignment)
 * implications