Does anyone have any intersting investigation topic I can do that is related to physics and of secondary school level, surrounding Cars and the mechanics of it, since I am intersted in it? (e.g. How brake thickness effect efficiency?
How about a simple investigation into vehicle drag?
Build a small simple chassis with a plastic body (about 1:24 scale would be good). Put the car at the top of a short raised section of "road" (a wooden plank, or similar), and see how far the car goes on flat ground after it has run down the plank (you might need to create a smooth transition from plank to the ground using something like card).
Now do the same thing but with different body styles. Making sure to keep the total mass of the car the same in each instance to keep it a fair test.
Since everything other than the aero has stayed the same then you can deduce that the car which travels the furthest has the lowest drag.
You can make the investigation more interesting by building your car so that it can accommodate some scale drivers/passengers. The challenge then is to build the car with the lowest drag whilst accommodating them in a sitting position....
If you have access to a vacuum former then you can make different body styles very quikly....
You could get a leaf blower(or similar) an anemometer(wind speed measuring, could also be pitot, or something) a scale and a newtonmeter(or spring and measure displacement with spring constant known)
You could get downforce vs drag for several windspeeds..