bonked

I clearly have sparked some thinking to be done on the topic. I agree that the problem is much more complicated the P=F/A and that there are numerous variables which can throw off the numbers. How about this: apply paint to the tread of the tires. Drive the car over a piece of paper, creating an imprint. I will get my measurements from that piece of paper. Again, that only solves the tread's surface area problem. It doesn't fix the pressure problems.

I knew this experiment was faulty at best. He said if we came within 20% PE (percent error) of the listed weight, we would get 2 extra points on our next test. There was simply no way to get within 20% of the actual without fudging the numbers. *** I was wondering how the PSI even helped if we didn't have an initial measurement, like you were saying. We need the inital pressure subtracted from the final which accounts for the car's weight. You also brought up a good point about the walls of the tires themselves. Sounds like my teacher doesn't know what the heck he is talking about, and I usually stump him in class with questions he can't answer, however he should be able to answer them. He basically reads from the book.

Alright, so today in my science class we attempted to measure the weight of my teacher's 2006 Honda Civic. He claimed that by calculating the surface area of each of the tires, and the PSI in each of the tires, we could find the weight of his car. We used the formula P (Pressure)=F (Force)/A (Area) rearranged for this lab: F=PA Because we only had tire gauges that measured PSI and not Pa, we went with standard units (Inches for length/width, PSI for pressure, lbs for weight). The weight came out to be around 4000lbs, obviously WAY too high for a Honda Civic. The posted weight was 2628lbs. However, the measurements we got could NEVER have worked out because the posted weight doesn't take into account gasoline. Also: the tread on the tire reduces the actual surface area (which means the surface area is wrong). Does this concept even make sense? Is it possible to do this, and do my problems with the experiment make any sense? Is my science teacher dumber then I am?