# Help with rolling cars -- science project

• Praline
In summary, a parent asked for help with their son's science fair project. The project involved rolling a toy car down a ramp and measuring the time and distance. The parent was unsure if the results were accurate due to the car bumping into the track. The expert explained that if both cars took the same amount of time to travel down the ramp, it means they had the same acceleration. However, the heavier car would have more kinetic energy and momentum, causing it to travel a greater distance on the flat surface. This was demonstrated in a video of an astronaut dropping a feather and hammer on the moon, where both hit the ground at the same time but the hammer had more kinetic energy.
Praline
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.

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.

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.

## 1. What is the purpose of a rolling car science project?

The purpose of a rolling car science project is to demonstrate the principles of physics and motion through a hands-on experiment. By building and testing a rolling car, students can learn about concepts such as friction, momentum, and energy.

## 2. How do I build a rolling car for a science project?

To build a rolling car for a science project, you will need materials such as a small toy car, cardboard, straws, rubber bands, and tape. You can follow a step-by-step guide or create your own design, but be sure to include a way to measure and change the angle of the ramp to test the car's speed and distance.

## 3. What variables should I consider when conducting a rolling car science project?

Some variables to consider when conducting a rolling car science project include the angle of the ramp, the surface of the ramp, the weight of the car, and the type of wheels on the car. You can also explore how different surfaces or obstacles affect the car's motion.

## 4. How can I make my rolling car go faster or farther?

You can make your rolling car go faster or farther by adjusting the angle of the ramp, using smoother wheels, or reducing the friction between the car and the ramp. You can also try adding weights to the car or using a steeper ramp to increase the car's potential energy.

## 5. What can I learn from a rolling car science project?

A rolling car science project can teach you about the laws of motion, such as Newton's first and second laws, and how different factors can affect an object's motion. It can also help you develop important skills such as problem-solving, data collection and analysis, and critical thinking.

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