King of the Hill Lab

Key Question
The objective is to build a car that is self propelled and can make it over the hill.

Car plan and Justification
Materials list : 1 small mousetrap ($5), 1 piece of cardboard($0.25), 4 bottle caps($0.50), 1 skewer($0.05), duck tape($0.05), 1 pen(1$), string($1), 10 to 20 little rubber bands ($1)

The car will be light so that it can go faster it will also be propelled by a mouse trap because it creates a big force to propel the car. The rubber bands around the wheels will create a small amount of friction so that the plastic bottle caps aren't too slippery

 


The force that will act on our car is the force of the mouse trap. Since it is tied to the skewer the skewer will be pulled by the force of the mouse trap. The car will accelerate at the start of the race because it will go from stopped to speeding up then it will slow down as the force of the mouse trap is no longer there and it finishes going up hill. Our car is not that massive and weights very little which means it will have a higher velocity to balance out the force. Newtons first and third laws apply to this because the car continues to move after even after the force is applied also as the car accelerates the mouse trap is applying a lesser force whites decreasing. At the top of the hill the car will start to lose momentum and impulse.

Analysis
I am disappointed with my cars performance because I believe if we would have been able to test it more before the race we could have been able to fix the wheel better. I think we were just unlucky.


Ramp Test evaluation

• We did not make any modifications from our original plans.
• Our car had a big displacement. It came out quick with a lot of acceleration then started to slow down as it approached the top of the ramp.
• The car did not perform as expected due to the positioning of the wheels because it kept turning to the side. It did go a good see just right into the wall.
• The only modification is the replace the wheels so the car can go straight.

Evidence

Our car was not successful in the end. We could not get the wheels straight. The cars that were the most successful in this project were the ones that were more massive and had bigger mouse traps. Since the mass and the force were increased the time it took for the car to accelerate also increased which is a good strategy for a race like this because it needs enough time and force to get up the hill. It is also good for a car to be more massive because it can overpower smaller cars. I would improve by using a bigger mouse trap and making sure the wheels are straight. 

yes, being well constructed wins out over everything...  :)

Ticker Tape

Isabel Gonzalez
NG 1 - What is the relationship between position and time for a cart rolling down a ramp?
The time stays the same but the position increases because the cart is accelerating since there is no friction.

What is the relationship between velocity and time for a cart rolling down a ramp?
The time stays the same but the velocity increases proportionally. time stays the same??  what does that mean?

NG 2 - Investigating

First we set up the ramp at an angle by propping it up with 2 boxes. Next we set up a 60 Hz ticker timer using carbon paper. We taped the end of the carbon paper to the cart and placed it at the top of the ramp. We then let the cart go after turing on the ticker timer. The ticker timer made a motion map and I used that to calculate the time and position. Every six dots, which was 0.1 seconds, I calculated the position using a meter stick.

Table  
variable names?
0s   - 0cm

0.1s - 1.5cm
0.2s - 5cm
0.3s - 10.4cm
0.4s - 17.5cm
0.5s - 26.4cm
0.6s - 37cm
0.7s - 49.4cm
0.8s - 63.2cm
0.9s -79.4 cm

I cut my ticker tape every 6 dots because that counted as 0.1s then pasted it on the graph to show how the velocity changed every 0.1s

NG 3
Position Graph  I can't see this??

Verbal Model: As the time increases, the position increases increasingly
Math Model: x = (88.485 cm/s^2) t^2

Velocity Graph 

(I can't figure out how to rotate the pic)

VM: As the time increases the velocity increases proportionally.
MM: y = mx +b
         Vf =at + Vi
                 ^
slope =   (cm/s)/s = cm/s^2 what does the slope mean?
y-intercept?
DeltaX = 1/2 at^2

NG 4
The displacement is the area under the velocity graph. When plugging the slope of X and V into a chart we found that X is equal to 1/2 V so we replaced it with the variable a because it is the acceleration and t always stays the same. Therefore to find the change in position you use DeltaX=1/2at^2 equation.
The second equation is saying that the final velocity is equal to the initial velocity plus the acceleration. We know that a is equal to the slope of V and the units are equal to the change in y over the change in x. That simplifies to (cm/s)/s= cm/s^2. Every second of time (s^2) the velocity (cm/s) changes.

NG 5 
Each experiment didn't have the same numbers for the constant slopes because it all depended on the angle of the ramp. Some were higher and others were lower. One error could have been the measurements of the position on the ticker tape. Since I used a meter stick it is hard to make it exact. Something else I would like to test is my acceleration when I am running. It would be cool to race other people and see who had a greater acceleration and try to prove it. good ideas!

Marshmallow Shooter

Experiment 1

NG1 How far will the marshmallow travel using different length tubes?

NG2 Procedure: We cut the folders and rolled them up at different lengths . The shortest is 9 inches, then 12 inches, and the longest was 18 inches. We placed the marshmallow closest to the mouth in the tube so that it starts the same place every time. We had the same person blow and used the same marshmallow every time. We estimated where the marshmallows landed and used meter sticks to see how far it went.

NG3
IV: Length of the tube

DV: How far the marshmallow travels

CV: Same person shooting and how hard she blows

NG3 Data Table:

Tube Length        Distance

  9 in.       ----        99.6 in.

  12 in.     ----        125 in.

  18 in.     ----        137 in.

When the tube length increases the distance increases.

The longer the tube the more time you blow with the same force. When there is more time there is more velocity meaning more momentum because J = ΔP and J = F x T.

Experiment 2

NG1 Will the mass of the marshmallow affect how far they travel?

NG2 Procedure: We kept out the meter sticks in line to tell how far the marshmallows travel. Next we got 6 marshmallows. We taped 3 marshmallows together with scotch tape in a line. Next we taped 2 marshmallows with the same tape and finally we taped 1 marshmallow the same so that it would have the same friction as the rest of them. good!! We kept the starting point, shooter, and tube the same. Each time we estimated where the marshmallow landed.

NG 3 

IV: Mass of the marshmallow

DV: How far the marshmallows travel

CV: Same person shooting and how hard she blows

NG 3 Data Table:

      Mass              Distance

1 marshmallow -- 185.5 in.

2 marshmallows -- 89 in.

3 marshmallows -- 71 in.

When the mass increases the distance decreases.

Force*Time=mass*velocity 

B force x C Time = 3 marshmallows x lower velocity 

B Force x C Time = 1 marshmallow x higher velocity 

good!

Experiment 3

NG1 How far will the marshmallow travel when starting at different heights?

NG 2 Procedure: 
We used the same shooter, 12in. tube, force and marshmallow. First the shooter stood on a chair, then on her feet, and finally on her knees. We did 2 trials of each by estimating where they landed and then took the average and used one number.

IV: Height of the starting point

DV: How far the marshmallows travel

CV: Same person shooting and how hard she blows

NG3 Data Table:

    Height             Distance

Chair(80 in.) ---     91 in.

Standing(60 in.)--- 82 in.

Knees (34 in.) ---  74.5in.

When the height increases the distance increase.
Speed is the same but the time to fall is different. The higher the longer time to fall.

NG4-5
From these experiments we have now proved that J=ΔP (impulse = momentum). This is because J= F x T (impulse = force x time) and F x T = M x ΔV (Force x time = mass x change in velocity).
This is proved by our first experiment. The force stayed the same but the amount of time increased which means increase velocity and also momentum. For example, with the 9 in. tube, the marshmallow will have the same force applied as the rest but for not as long since it is shorter. This means there is less momentum therefore it the marshmallow won't travel as far. The longer the tube the more time the same amount of force is applied on the marshmallow. 
In our second experiment we noticed that as the mass increases the distance the marshmallow travels decreases. This is true because since the force and time are equal to mass and velocity when one goes up the other gets lower. When there is one marshmallow the velocity increases because it is equal to the impulse that is given to all of the other different marshmallow masses. When the marshmallow mass increases the velocity decreases because it is still equal to the same impulse. good!
In our third experiment we learned something different. The force, and time mass, and velocity stay the same but the height of the marshmallow increases. The higher the marshmallow starts, the amount of time the marshmallow has to fall increases. When the height increases the distance increases.

Error analysis
In our experiments there are many things that we could have done better on. Something we could have done to improve was to get a machine like a fan to blow out the marshmallow so that the same amount of force would be applied more precisely. We could have also recorded all of the trials to try to get a better estimate of where the marshmallow landed each time. what do you mean all of the trials?