does weight affect speed??

[alyssastar]

Hello, my name is Alyssa and I am doing a project on weight affecting speed. I need experts on this topic, just to give me some background research for my board. Just at least one interesting fact about this subject (not the answer!) All I need are some primary sources...

Thank you!
-Alyssa

[rmarz]

alyssastar - Your question is kind of incomplete, therefore tricky. I can give you a couple of examples that demonstrate that weight (or more correctly, mass operating in the environment of earth's gravity) can have a distinct effect on the speed of an object being acted on by a force. In all cases this difference is a result of friction. Let's take the case of a common brick that weighs 4 pounds. If you place it flat on a smooth surface and apply a sufficient force to move it, it will reach an equilibrate speed of 'x' at a constant applied force of 'y'. If you take the same 4 pound brick, attach two axles and wheels that freely turn, apply the same propelling force, the equilibrate speed will be much faster due to the greatly reduced friction. Same weight (mass), much different speeds, the variable is friction. Increasing the weight in any fixed friction environment will always decrease the speed with a given applied force.

I think you have to state your hypothesis in terms of describing the weight, friction elements and applied forces to make a better demonstration of your experiment. While we are talking about moving an object across a smooth surface, consider a mass, or weight, that is dropped and free-falling, only acted on by gravity. Allowing for small differences in friction caused by air resistance, objects of very different weights will essentially fall (or really accelerate) at the same rate. This further proves that the variable that is underlying your premise is again, friction.

Rick Marz

[drkmarsh]

Hi Alyssa,
My sense is that you are just trying to satisfy the requirements for your poster without understanding the purpose of consulting with an expert. Do you want suggestions of what to research? Do you want to know about careers or current research that relates to your project? Here is an example of how to use an expert in your background research. One of my students investigated the question of whether packing or buying lunches affects memory, fitness and energy. She interviewed the woman that plans the meals for our school to find out what goes into our lunches and regulations. She put that information in her background research. My suggestion is that you research and learn about Newton's Second Law (Acceleration = Force / mass). Write back when you have done some basic research if you still want more clarification about a specific aspect of what you are trying to understand or apply to your project. A good expert question is something specific about your project and could not be found in a book. Good Luck!

[spherical]

Alyssa,

I am hoping you come back to this thread because I am doing an experiment that takes on similar qualities. I am testing mass, structure, etc. of baseball and putting them in to a pitching machine 100 times each. The same ball every time, so I need to measure wear as well...