Objects in Motion

Ask questions about projects relating to: aerodynamics or hydrodynamics, astronomy, chemistry, electricity, electronics, physics, or engineering

Moderators: MelissaB, kgudger, Ray Trent, Moderators

Objects in Motion

Postby eporambo » Sun May 20, 2012 1:35 pm

Using a tennis ball, a standard size marble, and a 1 inch diameter ball bearing, on the same measured course, using the same ramp height, will their mass affect their speed?
eporambo
 
Posts: 1
Joined: Sun May 20, 2012 1:28 pm
Occupation: teacher
Project Question: n/a
Project Due Date: n/a
Project Status: Not applicable

Re: Objects in Motion

Postby grai » Sat Jan 25, 2014 6:17 pm

Theoretically, speed is not affected by the mass of the objects. As you described, if three balls are released on a ramp, they will reach the end of the ramp at the same time. Therefore, the speed of the of the objects are all the same. This is due to the gravitational pull of the Earth on the objects and their ratios of weight to mass. If you were to test this, you may find that the speeds (distance/time) are not exactly the same. Sometimes factors like friction between the objects and the ramp and air resistance may throw your numbers off slightly. However, the speeds should be approximately the same.

Hope this helps and good luck with your experiment!
grai
Expert
 
Posts: 20
Joined: Sun Nov 03, 2013 12:51 pm
Occupation: Student
Project Question: To utilize my strengths in math and science and to help those students who have questions in these areas for their science projects.
Project Due Date: n/a
Project Status: Not applicable

Re: Objects in Motion

Postby Ray Trent » Tue Jan 28, 2014 10:51 pm

While their mass *by itself* will not affect the speed, the *distribution* of the mass *will*. Things rolling on ramps don't behave the same way that things falling through air do.

Their behavior depends on several factors, including density (because of air resistance, mostly), surface qualities (e.g. are they sticky, frictionless, fuzzy, have big air-trapping cones on them :-), irregular, etc.), and in reference to your question their "moment of inertia".

Moment of inertia, roughly speaking, changes depending on how much of the mass is distributed near the outside of the object, rather than in the middle. You can google or look in wikipedia (though don't use it as a primary source) for a good explanation of what this concept is, though some of these a pretty complicated.

A nice simple explanation of how this applies to objects rolling down ramps can be found here: http://www.batesville.k12.in.us/physics ... e_roll.htm
../ray\..
Ray Trent
Expert
 
Posts: 201
Joined: Wed Aug 24, 2005 3:07 pm


Return to Grades K-5: Physical Science

Who is online

Users browsing this forum: No registered users and 3 guests