Bottle Rocket Lab Homework: Calculating Initial Velocity

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In summary, the conversation discusses the launch of rockets made from 2L bottles using pressurized water in a class setting. The rocket's angle, height, hangtime, acceleration, and mass are given, and the goal is to find the initial velocity of the rocket. The homework equations and attempt at a solution are also mentioned. The use of constant acceleration and the possibility of air resistance are brought up, and it is suggested that the acceleration given may not be accurate. The poster also expresses confusion and requests help.
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lacrosselem
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Homework Statement


In class we made rockets out of 2L bottles and launched them using pressurized water.
The angle that ours went at was 50 degress. Height was 26m. Hangtime 5.18s
acceleration 3.8m/s2 and the mass of the rocket was .52kg

Homework Equations



I am trying to find the initial velocity of the rocket.
vi=vf-at
only problem with that is that I don't have the final velocity either.

The Attempt at a Solution


I honostly have no idea where to start. I have no clue. Help please!
Thanks!
 
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  • #2
lacrosselem said:

Homework Statement


In class we made rockets out of 2L bottles and launched them using pressurized water.
The angle that ours went at was 50 degress. Height was 26m. Hangtime 5.18s
acceleration 3.8m/s2 and the mass of the rocket was .52kg

Homework Equations



I am trying to find the initial velocity of the rocket.
vi=vf-at
only problem with that is that I don't have the final velocity either.
It looks like you are studying motion with constant acceleration. We can do the problem by ignoring air resistance, but I suspect that is not really valid for a 2L plastic bottle going through the air.

If vf is the velocity when the bottle hits the ground, it would equal -vi. Also, where do you get that the acceleration is 3.8 m/s^2?

The Attempt at a Solution


I honostly have no idea where to start. I have no clue. Help please!
Thanks!

p.s. bumping your post hinders getting a response at our forum, since it creates the impression that your post has been replied to already and then people are less likely to bother reading your question.
 

Related to Bottle Rocket Lab Homework: Calculating Initial Velocity

1. How do I calculate the initial velocity of a bottle rocket?

To calculate the initial velocity of a bottle rocket, you will need to measure the distance the rocket travels and the time it takes to travel that distance. Then, use the equation v = d/t, where v is the initial velocity, d is the distance, and t is the time. Make sure to use consistent units for distance and time (e.g. meters and seconds).

2. What factors can affect the initial velocity of a bottle rocket?

The initial velocity of a bottle rocket can be affected by several factors, such as the amount of water and air inside the bottle, the angle at which the bottle is launched, and the design of the rocket itself. Wind and air resistance can also play a role in the rocket's initial velocity.

3. How can I improve the accuracy of my initial velocity calculations?

To improve the accuracy of your initial velocity calculations, make sure to take multiple measurements and calculate the average. You should also make sure to use precise instruments for measuring distance and time, and carefully control the variables that can affect the rocket's velocity.

4. Can I use the same initial velocity calculation method for different bottle rocket designs?

Yes, you can use the same calculation method for different bottle rocket designs. However, keep in mind that the initial velocity may vary depending on the design and other factors mentioned in question 2. It is important to carefully consider these factors when comparing the initial velocity of different bottle rockets.

5. Are there any safety precautions I should take when conducting a bottle rocket lab?

Yes, it is important to take safety precautions when conducting a bottle rocket lab. Always wear safety goggles and make sure to have a clear launch area with no people or objects nearby. Follow all instructions and use caution when handling the rocket and launching it. It is also recommended to have a fire extinguisher nearby in case of accidents.

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