Rocket Car Quaetion
Posted: Tue Feb 02, 2021 1:39 pm
My son who is in the 5th grade used a model rocket engine powered car for his science fair project. He added weight to the car and asked the question "Will changing the weight of the car change the speed of the car?"
He found that adding more weight decreased the speed. I want to make sure he understands why this happened, and I need a little clarification. Should he ask "Will changing the mass of the car change the speed of the car?" Is the slower speed because of Newton's second law? Since there was a change in the mass and the force stayed the same then there was an inverse change in the acceleration. I understand that acceleration and speed are not the same, and I want to make sure that I am explaining this correctly and using the terminology correctly. Since the car is moving in a straight line is it correct to state that the added mass decreases the acceleration which decreases the speed?
He also launched the car going up a slope and asked the question "Will changing the slope of the ground change the speed of the car?" Would it be better to say "Will the rocket car's speed decrease when going up an inclined plane?" The car went slower going up the slope. Was this because of gravity pulling the car down the slope requiring more force? Is this also Newton's second law? Is it correct to say the same force was used (model rocket engine), but the gravitational force worked against the force of the model rocket engine decreasing the overall force? All of the research he found was about going down a slope not up. I couldn't find an easy answer either. Apparently most people test rolling things down slopes not launching them up slopes.
Thank You,
Hope
He found that adding more weight decreased the speed. I want to make sure he understands why this happened, and I need a little clarification. Should he ask "Will changing the mass of the car change the speed of the car?" Is the slower speed because of Newton's second law? Since there was a change in the mass and the force stayed the same then there was an inverse change in the acceleration. I understand that acceleration and speed are not the same, and I want to make sure that I am explaining this correctly and using the terminology correctly. Since the car is moving in a straight line is it correct to state that the added mass decreases the acceleration which decreases the speed?
He also launched the car going up a slope and asked the question "Will changing the slope of the ground change the speed of the car?" Would it be better to say "Will the rocket car's speed decrease when going up an inclined plane?" The car went slower going up the slope. Was this because of gravity pulling the car down the slope requiring more force? Is this also Newton's second law? Is it correct to say the same force was used (model rocket engine), but the gravitational force worked against the force of the model rocket engine decreasing the overall force? All of the research he found was about going down a slope not up. I couldn't find an easy answer either. Apparently most people test rolling things down slopes not launching them up slopes.
Thank You,
Hope