Rocket Projectile Practicum Post

Experiment:
Our task was to take a rocket and predict where it will land using our formulas from our unit on projectile motion.

Materials:
Rocket
Angles
Bike Pump

Steps:
1. We found the actual velocity of the rocket by testing it at a different angle and seeing how far it went. We worked backwards using trigonometric ratios.

2. We started with an angle of 25 degrees and found that the actual velocity of the rocket at the time of takeoff was 19.92m/s.

3. We then could predict the time using the viy (from the new angle (40 degrees)) and the equation
x = 1/2at^2+vit

We found the time as 3.114s

4. We next found the change in position using equation Vx = (change in) x/ t

Change in position: 39.87m

Conclusions:
The actual position of the rocket was 32.9m. We were somewhat off in our calculations, but I think it was because of the wind on the day that we first tested. If the wind speed had been constant, I believe that our prediction would have been correct.

This is a picture of the calculations I took

Unknown Mass Cart Practicum

Procedure:
The task of our group was to try and find the mass of an object placed on a cart using our momentum equations. We were given a cart, a bag of salt (unknown mass), and capstone sensors. 

Steps:
1. We knew that the mass of the empty cart was 0.5kg (Ma). We then measured the velocity of the cart so we found the Va.
2. From here we found the velocity of the cart with the bag of salt. (Vab)
3. Using the law of conservation of momentum.

mava + mbvb = (ma + mb)(Vab)

Evaluation and Manipulation of Data:

Diagram of our experiment. Drawing courtesy of Miranda Thompson (a group member)

pbefore = pafter
mava + mbvb = (ma + mb)(Vab)

(0.5)(0.57) + (mb)(0) = (0.5 + mb)(0.24)

(0.28)+ 0 = .12 + .24mb

.28 - .12 = .24mb

.16 = .24mb

mb = .66kg

Conclusions:

The actual weight was .77kg, so we were a little off, but I think it's mostly due to lack of time to do a lot of trials for the velocity before and after. We took the average of 3 trial runs when calculating the velocity.