Summer Challenge

You may have better things to do during the summer vacation but, in case you find yourself getting bored, I have an investigation that you might like to tackle. The work is open to all of my students, both those of you who are still studying the GCSE course and those who have just finished and are now waiting for your results.

At the end of term I set up a ramp and rolled a toy car down it using the force of gravity alone. The car then had various pieces of card attached to it, acting like a sail that created extra air resistance. Your task is to analyse the data and produce an appropriate conclusion.

This investigation is the basis of many real-world applications for objects that move through the air (or other fluids). It also applies to fluids that move past stationary objects. This means that the idea of drag, which is what this is all about, is just as important when designing cars as it is when thinking about coolant flow through a nuclear reactor!

Don’t worry, the set-up that I’ve used is extremely simple – so should be fairly easy to analyse.

The challenge is contained in this document.

There is also a spreadsheet containing the summary data and a graph, which you can download here.

I’ve decided that I will award a prize (maybe two) for the best entry (or entries). Your analysis must be delivered to my lab at the start of next term. If you can’t deliver your submission in person, then either email it to me or get somebody else to drop it off. You can even send it by old-fashioned postal mail if you wish!

For those of you who want to dig deeper, a quick web search will uncover the equation that predicts the drag force acting on a moving object. You will see, probably unsurprisingly, that the drag force is directly dependent on the effective area: let’s say that this is just the area of the piece of card I attached to the roof of the toy car. But you will also see that the drag force does not depend directly on the velocity.

I won’t go into more detail because this is YOUR challenge.

I look forward to seeing what you come up with in your conclusion.

Good luck!