Does mass affect speed?! DUE TOMORROW!!!! HELP!!!!!!!!

[cecilia766753]

Okay so I need to interview an expert and for some reason last week when I tried this it didn't go through so I'm trying again

Does the mass of an object affect the speed that it will travel when force is applied to it?

[ScienceExpert123]

Yes, Force=Mass x Acceleration (F=MA), therefore more force is needed to move more mass...and more force is needed to move objects faster, the more mass they have.

Acceleration= (the change in velocity (final velocity- initial velocity))/time.....if an object is at rest, the initial velocity is 0 meters/second, so basically the force needed to move an object at a certain speed = the mass of the object x (the velocity of an object/ the time over which the object is being pushed)

overall, the more mass, the more force is needed to move an object of higher mass

let me know if you have any more questions

good luck,
scienceexpert123

[deleted-37163]

Hi,

Just adding on to ScienceExpert's post--

If you think of inertia, or the tendency of an object to resist motion, you can intuitively realize that objects with more mass have more inertia and are thus harder to move.

Other than that, is there any specific project we can help you with? For future reference, the Expert forum is directed toward science project help. We would be happy to help you with any project you might have.

Hope this helps,

Manjinder

[cecilia766753]

Hi. I already posted a topic earlier but I just wanted to post a follow up question.

My experiment for this topic is that I will buy three soccer balls of different size (size 3, 4, and 5). I will roll each soccer ball down a ramp three times and calculate the averages to see which soccer ball traveled to the destination (13 feet away from the bottom of the ramp) quicker (I will time how long each soccer ball took to reach the destination). My hypothesis (based on Newton's Second Law) is that the size 3 soccer ball will reach the destination quicker than the other balls, because it has less mass than the size 4 and 5 soccer ball. Do you think that my hypothesis is correct? If not, what would your hypothesis be?

[MelissaB]

Hi,

Please keep all your posts in the same thread so the experts can better help you.

Thanks!

[ScienceExpert123]

Dear cecilia766753,

Hypotheses are not meant to be correct or wrong before the experimentation....whatever your hypothesis is, is fine. Basically you are doing these experiments to prove if your hypothesis is right or wrong, and then you will describe why it was right or wrong....you won't be penalized because your hypothesis was wrong.

Regarding the soccer balls, your hypothesis may or may not be wrong, considering momentum and potential and kinetic energies. potential energy= mass x force of gravity x the height above the ground, so the more mass something has, the more potential energy it has. Due to the law of conservation of energy, the more potential energy something has, the higher its velocity will be because the potential energy has to be converted to kinetic energy when the object moves (kinetic energy= (1/2) x mass x velocity squared (v^2)
I think you should keep your pre-existing hypothesis and see if it's correct or not
By the way, you can actually calculate how fast each of the balls should go using physics formulas, but you would need to know the mass of the balls, the height of the ramp, and the angle of the ramp to the ground.

I know this stuff can be complicated, so let me know if you have any questions.

good luck,
scienceexpert123

[deleted-37163]

Hi!

This project is starting to get really interesting. ScienceExpert gave some great advice- do the experiment first and then try to analyze why or why not your observations fit your hypothesis.

To delve a little further, according to my calculations, in a theoretical experiment where all objects were of the same size and makeup, they should all drop at the same final speed no matter which has the most mass. Check out this link:
http://galileoandeinstein.physics.virgi ... accn96.htm

As Galileo proved, it is air resistance that makes it appear that heavy objects fall faster. In reality no matter which ball is the heaviest, they should theoretically all fall down with the same speed in the absense of air resistance. However, since the balls are rolling down and not sliding, some energy goes into the rotational motion of the ball. According to the law of conservation of energy: mgh = 1/2mv^2 + 1/2 I (rotational speed) ^2, where I is usually proportional to the mass. Because of this, the mass cancels out and should not affect the rolling speed. In fact, it should be the radius of the ball that affects the rolling speed. Naturally, heavier balls are bigger and they thus roll faster because of their size, not their mass.

If you took rotational motion out of the picture and you had blocks sliding down a ramp without regards to friction, they would all have the same final speed, irrespective of their mass.

Hope this helps,

Manjinder

[bobmelbin]

In our experiment we rode a skateboard from point A to point B (slightly downhill). Three people of significantly different size and weight rode three times each. The heaviest person went the fastest, the lightest person went the slowest. Why?

[deleted-71827]

Hi,
A simple answer to your question can be found here:

http://wiki.answers.com/Q/How_does_weig ... skateboard

If you want to learn more about inertia and friction, you might want to check out the ScienceBuddies project guide:

https://www.sciencebuddies.org/science- ... p012.shtml

Good luck!