a. Newton's first law of motion states that when an unbalanced force acts on an object, the object accelerates. In the balloon car lab, one of the forces was the air rushing out of the balloon, causing the car to accelerate forwards. Gravity and air resistance were the other two forces acting on our balloon car. Gravity caused the car's wheels to slow down and eventually stop spinning while air resistance limited the speed that the car could accelerate with.
b. Newton's second law of motion states that when an object has a higher mass it takes more force to move the object. The wheels on our balloon car had a relatively high mass, which made the car heavier, so it took more force to make the car start moving.
c. Momentum is mass times velocity so if there is a high mass and a high velocity the car will have a greater momentum when it runs out of air and therefore will travel a greater distance without fuel of any kind. The law of momentum and Newton's second law contradict each other in some ways. One law states that less mass is better and the other states that more mass is better.
d. Newton's third law of motion states that an action force always has a reaction force. In this case, our balloon car's action force was when the air left the balloon and the reaction force was when the car went forward. When the car was released, air started rushing out of the balloon hitting the air molecules that where already there, causing those molecules to hit the ones that had just come from inside the balloon and the car went forward.
e. All three different types of friction act on balloon cars. The air resistance against the car is a kind of fluid friction. While the skewers that we used as axles rubbing against the car, was sliding friction. And the wheels rolling across the floor was an example of rolling friction.
a) Although air resistance and gravity are important, how does friction come into play? (It makes the object in motion stop.) Mention inertia and the fact that the initial force overcame inertia.
ReplyDeleteb) State that Newton's 2nd law is F=ma. If the wheels had a high mass, what does this say about the acceleration?
c) If the 2nd law and momentum contradict each other, which approach did you take? (Did you try to go for the lower mass and high acceleration or the higher mass and higher momentum?) WHY will the car have a greater momentum when it runs out of air?
d) I think you have the right idea but the explanation is a bit unclear. The action force is the air from the car pushing on the surrounding air. The reaction force is that air pushing on the car, which makes the car go forward.
e) Define friction and the three types. Elaborate on the examples. Mention that friction slows the car down. How did friction affect your car during the trials?