Help with rolling cars -- science project

Click For Summary

Discussion Overview

The discussion revolves around a science project involving toy cars rolling down a hill, focusing on the effects of added weight on their motion and distance traveled. Participants explore concepts related to acceleration, kinetic energy, and the influence of mass on motion, aiming to clarify the results observed in the project.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that both cars traveled downhill in the same amount of time, suggesting they had the same acceleration.
  • It is proposed that the net forces acting on the cars, when divided by their masses, yield the same acceleration for both cars.
  • Another participant points out that despite the same time, the heavier car must have greater kinetic energy and momentum, leading it to travel farther on the flat surface.
  • A reference is made to a video of an astronaut dropping a feather and a hammer on the moon, illustrating that different masses can have different kinetic energies while still hitting the ground simultaneously.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the observed results, particularly regarding the relationship between mass, acceleration, and distance traveled. No consensus is reached on the correctness of the project's findings or the explanations provided.

Contextual Notes

The discussion includes assumptions about frictional forces being constant and does not resolve the potential impact of experimental errors on the results.

Who May Find This Useful

This discussion may be useful for parents, educators, or students interested in understanding basic physics concepts related to motion, mass, and energy in a practical context.

Praline
Messages
2
Reaction score
0
I'm sure this is elementary for this forum, but can someone help me figure out if my son's science fair project results are correct? He rolled his toy car, with and without weight added, down hill and measured the time to get to the bottom of the hill and the distance traveled once the car hit the flat part of the track. He kept bumping into the track and messing it up so I'm not sure if his results are accurate. He has both cars traveling down hill in the same amount of time and the heavier car traveling farther. Does that sound right? How would you explain it in elementary age terms? Thank you in advance.
 
Physics news on Phys.org
Praline said:
He has both cars traveling down hill in the same amount of time and the heavier car traveling farther. Does that sound right? How would you explain it in elementary age terms? Thank you in advance.

his both cars are traveling taking same amount of time it means the cars had same accelerations
so if net force experienced by cars were say F(L) and F(H) were such that

F(L)/M(L) = F(H)/M(H) = acceleration
so their velocities after traversing the ramp -touching the flat surface must be same-
but you are saying that they traveled different distances on flat surface...
there is a catch - on coming down their kinetic energy must be different the heavier one having larger kinetic energy and momentum than the lighter one ;
therfore the heavy one gets to stop after traversing larger distance (taking the frictional forces to be same.)
this is just my guess- may be some one can enrich us.
 
  • Like
Likes   Reactions: Praline
drvrm said:
his both cars are traveling taking same amount of time it means the cars had same accelerations
so if net force experienced by cars were say F(L) and F(H) were such that

F(L)/M(L) = F(H)/M(H) = acceleration
so their velocities after traversing the ramp -touching the flat surface must be same-
but you are saying that they traveled different distances on flat surface...
there is a catch - on coming down their kinetic energy must be different the heavier one having larger kinetic energy and momentum than the lighter one ;
therfore the heavy one gets to stop after traversing larger distance (taking the frictional forces to be same.)
this is just my guess- may be some one can enrich us.
Thank you! That is so helpful!
 
See video of the Apollo astronaught dropping a feather and hammer on the moon. Both hit the ground at the same time but the hammer has more KE.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
955
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 2 ·
Replies
2
Views
894
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 66 ·
3
Replies
66
Views
6K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
10K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 3 ·
Replies
3
Views
4K