Rocket Definition and 1000 Threads
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Landing reusable booster rockets
a=v-u/(t) a=0-172/(13) a=approx -13m/s^2 * a=Fnet/m -13=Fnet/25000 Fnet=-13(25000) Fnet=-3250000N Fg+Fth=-325000N Fth=-325000-245000 Fth=-670000N Any hints as to where have I gone wrong?- paulb203
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- Physics Rocket
- Replies: 35
- Forum: Introductory Physics Homework Help
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I Can Staging Rockets Achieve Faster-Than-Light Travel Despite Relativity?
I have heard this before many times, ‘we can’t reach some parts of our universe because of expansion’ but can we launch a massive rocket and then launch a rocket from the first rocket in the same direction and then again and again? Due to relativity.- benss
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- Rocket Space Travel
- Replies: 8
- Forum: Astronomy and Astrophysics
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Best rocket-stopping method
Does anyone have a good method for stopping a model rocket while it is still going up without reverse propulsion?- Rocket Maker
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- Method Rocket
- Replies: 45
- Forum: Aerospace Engineering
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Could a nuclear powered rocket be safely launched from Earth?
I was scrolling through YouTube and saw this video: The video showcases the Project Orion rocket. Project Orion was a theoretical spacecraft propulsion concept which uses nuclear explosions to propel a rocket. Opening the comment I further learned that it was discontinued due to Nuclear Test...- Nabir14
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- Nuclear Rocket Space
- Replies: 21
- Forum: Aerospace Engineering
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Model Rocket Stabilization
Hello everyone, I am making a model rocket and want it to be as stable as possible I was wondering what is the most effective stabilization method for a small model rocket. I was thinking of spin stabilization.- Rocket Maker
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- Model Rocket
- Replies: 18
- Forum: Aerospace Engineering
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Calculating drag for high mach numbers
Ok, so i have a high powered rocket i made and it hits about 420 m/s At low mach numbers, most the drag is due to skin friction, hence why you can solve for the Cd based on the Re and geometry alone (Dr. Gerald M. Gregoreks work shows this) However, as soon as you hit higher mach numbers...- LT72884
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- Mach Rocket
- Replies: 4
- Forum: Aerospace Engineering
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B Calculating Heat from Drag force on a Rocket Airframe
Ok, so i have a question, and an approach to my question. Am i going in the correct direction? Here si the question: I have a high powered rocket i made. It sometimes hits mach 1.9. I would like to calculate the heat generated from going that fast so i can test other materials. Here is what...- LT72884
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- Drag Heat Rocket
- Replies: 24
- Forum: Classical Physics
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Failed rocket problem (momentum conservation, Kleppner 4-4)
Hi, Can anyone hint me if there is issue in the problem statement? Consistent answer can be obtained if one presumes that the trajectory of center mass is parabolic. Assuming this, the CM will land at distance L right to the axis of symmetry of parabola. But the problem tells about a rocket...- Michael Korobov
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- Momentum conservation Rocket
- Replies: 3
- Forum: Introductory Physics Homework Help
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I NASA is seeking a faster, cheaper way to bring Mars samples to Earth
Would it be possible to send a rocket to Mars containing a number of shaped charges that could be directed at the surface, timed and positioned to direct the excavated material back towards Earth for collection above the atmosphere?- Colin Wilson
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- Mars Rocket
- Replies: 6
- Forum: Other Physics Topics
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I Is there a way to calculate how rocket exhaust gas spreads out in empty space after leaving the rocket?
I haven't found anything obvious about how rocket thrust gas particles would expand once they leave the thruster of the ship from which it is ejected. Inside the rocket would be the exploding gas, but outside the rocket the temperature would be ~ 3 Kelvin and zero pressure since outer space...- Albertgauss
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- Exhaust Rocket
- Replies: 3
- Forum: Classical Physics
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Find the amount of work done against gravity in moving a 150kg rocket
I started by calculating the energy at the Earths surface, which is just -G(150)(6 x 10^24)/(6400 x 10^3) = -0.9 x 10^10, and calculating the energy at the orbit radius, E = -G(150)(6 x 10^24)/(18000 x 10^3) = -3.4 x 10^9, then doing some subtraction we have -3.4 x 10^9 - (-0.9 x 10^10) = 5600 x...- sdfsfasdfasf
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- Gravity Rocket Work
- Replies: 4
- Forum: Introductory Physics Homework Help
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B What limits a rocket's max speed if in space drag is zero?
What limit rocket max speed if in space drag is zero? If drag is zero and thrust is constant that mean rocket accelerate all the time?- user079622
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- Drag Rocket Speed
- Replies: 68
- Forum: Classical Physics
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Help with final year uni course selection for defense and rocket industry
TL;DR Summary: Help with final year courses that will help for defense and rocket industry. Hello , what extra courses would be best to help with knowledge in defense/rocket industry as a mechanical engineer in final year. I am going to do thermofluid specilisations for my final year and I am...- nagaoka7
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- Engineering Rocket University
- Replies: 1
- Forum: STEM Academic Advising
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Ionizing Atmosphere on the nose of a rocket, missile or aircraft to reduce drag
I heard of a strange engineering concept that was mentioned to me by someone who claimed to be a retired aerospace engineer. It was a guy I met on the internet so I took what he said to me with huge grain of salt. He said something to me that I barely comprehend and I haven't heard from this...- paul3337
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- Missile Rocket
- Replies: 3
- Forum: Aerospace Engineering
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B Launch of a rocket - its initial displacement and velocity
so then when we model the velocity of the motion of a rocket (e.g., in a mathematics report), is it reasonable to assume that the initial velocity equals zero? I also apologise for my lack of information if I made a huge mistake in my question 🙏🏻- Saba
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- Motion Rocket Velocity
- Replies: 8
- Forum: Classical Physics
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Rocket propelled by a beam of photons
Before the engine is switched off: $$P_{Initial rocket} = (m_{i}c, 0)$$ $$P_{photons} = (E/c, -p_{photons})$$ where E is the energy of the photons and ##p_{photons}## is the 3 momentum of the photons. Rocket after engine switched off: $$P_{Final rocket} = (m_{f}c, m_{f}v)$$ By conservation of...- ruairilamb
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- Momentum Rocket
- Replies: 10
- Forum: Advanced Physics Homework Help
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What is the rocket's initial acceleration?
Help me solve... I'm getting errors here..- JoeDGreat
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- Physics Propulsion Rocket
- Replies: 6
- Forum: Introductory Physics Homework Help
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B Another special relativity related "paradox"
Full disclosure: I have asked this question on stackexchange too, but I think I didn't frame my question properly there, which probably led to misunderstandings and complicated answers. Plus some comments there led me to refine the question a bit so I hope it's in a good state now. I am new to...- sphyrch
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- Paradox Rocket Special relativity
- Replies: 15
- Forum: Special and General Relativity
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Why is the thrust equation same under gravitational force?
The homework statement isn't exactly as is mentioned above. The actual problem statement is as follows: This is problem 3.8 from John R. Taylor's Classical Mechanics; however, my question is not related to the main problem itself but one particular aspect of it. Now, in the same textbook (John...- f3sicA_A
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- Classical mechanics Momentum Rocket Thrust
- Replies: 10
- Forum: Introductory Physics Homework Help
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I Aircraft guidance question: Effect of mounting sensors at the CG vs on the Tail
Hi, Can I someone please explain to me, the moment behaviors of having something fixed on CG vs on Tail in a rocket? are there any benefits of having a Sensor on CG than fixed on the tail? Thank you- cessna1525
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- Moment Rocket Sensor
- Replies: 10
- Forum: Mechanics
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Water Rocket Science Project by Tanguy: Reach 11,2k m/s!
Hi ! I'm a French student in Terminale (12th grade equivalent) and I have to do an oral presentation of 5min (Grand Oral) for my baccalauréat linked with my professional project. As I want to become an engineer in astrophysics, I want to talk about water rocket and the theoretical possibility to...- Tanguy
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- Rocket Rocket engine Rocket problem Rocket science
- Replies: 14
- Forum: Introductory Physics Homework Help
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Rocket thrust equation in under-expanded nozzle
Hello, so the thrust equation goes like: F = (m dot)*v_e + A_e*(p_e - p_a), where F ... thrust [N] m dot ... mass flow rate [kg/s] v_e ... velocity of exhaust [m/s] A_e ... area of the exit nozzle plane [m2] p_e ... pressure of the exhaust at the exit of the nozzle [Pa(a)] p_a ... ambient...- pejsek
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- Nozzle Rocket Thrust
- Replies: 2
- Forum: Aerospace Engineering
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Where in orbit should a rocket fire to escape with minimum ΔV
I am really lost on how to deal with this. Since this is an elliptic orbit, the mechanical energy is negative. For the rocket to escape orbit, we have to get the mechanical energy to be equal to or greater than zero. I thought at first that it would escape in the perigee, since that's where the...- radio360
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- Escape Fire Minimum Orbit Rocket
- Replies: 17
- Forum: Introductory Physics Homework Help
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B Model rocket physics: Why doesn't the motor go through the nose cone?
For those who have built those small model rockets, please help me understand a very very simple physics problem that i for some reason do not fully get. Why is it that the motor tube does not have a retention ring on it, to prevent the motor from flying out the nose cone? i know it cant be...- LT72884
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- Cone Model Model rocket Motor Physics Rocket
- Replies: 8
- Forum: Classical Physics
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Rocket acceleration problem: confused about Newton's 2nd Law
TL;DR Summary: I approach a rocket acceleration problem using two approaches: F=d(m*v)/dt and F=ma. The resulting differential equations are different. What am I doing wrong? We have a ship with a mass-reaction rocket engine floating in space. The initial mass of the ship (including fuel) is...- aniseed
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- 2nd law Acceleration Confused Law Newton's 2nd law Rocket
- Replies: 42
- Forum: Introductory Physics Homework Help
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Finding the terminal velocity of a model rocket from a list of velocities
Ok, i have some rocket data from a 20,000 foot launch. I have the times, altitudes, and velocity at said time. Is it possible to find the terminal velocity from this long list of numbers? I tried graphing the velocities to see where the curve flattens out, since usually that is where terminal...- LT72884
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- List Model Model rocket Rocket Terminal velocity Velocity
- Replies: 165
- Forum: Classical Physics
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B Speed of light and this Accelerating Rocket scenario
Hello, I have a question linked to gravity and speed of light : According to the Special Theory of Relativity, the speed of light cannot be exceeded because it would need an infinitive energy to accelerate the relativistic mass of a moving objet (a space craft for example) : indeed if the...- John SpaceY
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- Light Rocket Speed Speed of light
- Replies: 45
- Forum: Special and General Relativity
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B Calculating Fuel Efficiency of Rocket Going Near c
How would you calculate the fuel efficiency of a rocket (around 10 tonnes) going near the speed of light?- Peter564
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- Efficiency Fuel Rocket
- Replies: 2
- Forum: Special and General Relativity
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Is Rocket Lab's Neutron Rocket a True Competitor to SpaceX's Falcon 9?
The Neutron is the rocket that Rocket Lab intends to compete with SpaceX's Falcon9. Still in development Rocket Lab is planning to use composites for tankage and airframe. Didn't SpaceX try this for the Falcon but abandoned it in favor of proprietary stainless steel...- gleem
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- Neutron Rocket
- Replies: 1
- Forum: Aerospace Engineering
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I Measuring Model Rocket Velocity: Is it Possible?
Question, if i record a video of a model rocket launching, and then falling, is it possible to get the actual (or extremely close) velocity every 1 second? thanks- LT72884
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- Measuring Model Model rocket Rocket Velocity
- Replies: 17
- Forum: Other Physics Topics
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Impact force of model rocket with parachute
I just launched a 2.2kg model rocket that stands about 5 feet tall and has a airframe that is 4 inches in diameter. I am trying to find how much the impact force is when the rocket hits the ground at 16MPH. Whats the best approach? Momentum? KE? or something else:) thanks- LT72884
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- Force Impact Impact force Model Model rocket Parachute Rocket
- Replies: 17
- Forum: Introductory Physics Homework Help
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B Can a rocket flame be controlled by a magnetic field?
An idea came to my mind after I saw the plasma reactor and how the plasma floats through a magnetic cage that prevents the nuclear reactor from melting, to make a magnetic cage that prevents the rocket engines from melting while they are working. Is this possible, or does it take a critical...- Ahmad Sadek
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- Field Magnetic Magnetic field Rocket
- Replies: 28
- Forum: Classical Physics
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Conservation of Momentum of Rocket Exploding after Takeoff
-Solved for vf using equation 3 to get 20.0m/s (speed before explosion) then solved for the distance to reach the explosion using equation 4, to get 20.0m, which felt wrong having the same numbers but that may just be coincidence. -Found the distance travelled of the lighter piece using 530m -...- hisiks
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- Conservation Conservation of momentum Elastic collision Momentum Momentum conservation Rocket
- Replies: 5
- Forum: Introductory Physics Homework Help
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Help with building a school rocket
Hello, I attend a physics club at my school and now, we are building rockets until winter. I need some help because I really want to beat the GCSE students. We are in self chosen teams and the winner is who gets their rocket the highest(hopefully it will go high enough so we can't see it) I have...- StellarisVoid
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- Building Rocket School
- Replies: 24
- Forum: Aerospace Engineering
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The Future of Rocket Propulsion, What To Do About Emissions
https://www.bbc.com/future/article/20220713-how-to-make-rocket-launches-less-polluting- Astronuc
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- Emissions Future Propulsion Rocket Rocket propulsion
- Replies: 4
- Forum: Aerospace Engineering
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Is the rocket equation correct using conservation of momentum?
I tried to use conservation of momentum I only want to know if the equation I came up with is correct and if not, why?- heyhey281
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- Rocket Rocket equation
- Replies: 8
- Forum: Introductory Physics Homework Help
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Can I make a rocket by mixing aluminum + iodine (+ water catalyst)?
Basically it's a well known reaction, many kids on youtube make it for the views: I am thinking, since AlI3 sublimes can it be put in say tungsten bottle (is this even a thing??) and then used as a rocket the same way Na+H2O or HCL+Al rockets are used - the gas escapes? This phase... -
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Change of ellipse while accelerating the rocket
When the rocket accelerates in space does its trajectory which is an ellipse change in size and not the focal points because the Earth is still in one of two and also the current height doesn't increase, right?- NODARman
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- Change Ellipse Orbital mecahnics Rocket Trajectory
- Replies: 3
- Forum: Aerospace Engineering
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B This rocket physics problem seems unrealistic
Ok, so here is what i am trying to do. Find apogee of a model rocket i built using a C motor, then i need to calculate terminal velocity, but something is not adding up, i get a really really high apogee, almost a mile. STAGE 1: I have a c6-7 rocket motor which provides 10N-s of impulse, and...- LT72884
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- Physics Rocket
- Replies: 17
- Forum: Classical Physics
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How Does the Sign of ##dm## Affect Rocket Propulsion Calculations?
I have a question. If we assume that ##dm## is positive, is the answer supposed to be different from the one when we regard the ##dm## as negative? 1. If I assume that ##dm## is positive: By using momentum conservation, we will get $$mv=(m-dm)(v+dv)+dm (v-u)$$ simplify the equation $$m \,dv=dm...- Rikudo
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- Mass Rocket
- Replies: 14
- Forum: Introductory Physics Homework Help
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Rocket Escape Velocity from the Earth-Sun system
I have a difficulty when making the energy-conservation-equation for the second step. When making the equation, we need to know the exact position (measured from the sun) of the rocket after it is freed from the Earth gravitation. But, where exactly does the rocket free from Earth...- Rikudo
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- Escape Escape velocity Rocket System Velocity
- Replies: 3
- Forum: Introductory Physics Homework Help
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B Andy Weir's "Hail Mary": Question About Relativistic Rocket
I am reading Andy Weir's Hail Mary. There was a part about relativity: it wrote, that a relativistic interstellar ship had lots of spare fuel, because the mission planners actually ignored relativity, and thought travel will be Newtonian. Am i wrong to think, that is nonsense, and the opposite...- GTOM
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- Relativistic Rocket
- Replies: 13
- Forum: Special and General Relativity
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Why Not Titanium Alloy Rocket Engine Nozzles?
Industry standard right now is a copper alloy (usually an aluminum bronze) inner liner to promote heat transfer to the coolant channels and the walls of the channels and outer liner are usually made of an INCONEL alloy, usually either 625 or 718. But INCONEL is VERY expensive and heavy. The...- Ozen
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- Alloy Engine Rocket Rocket engine Titanium
- Replies: 19
- Forum: Aerospace Engineering
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Scott Manley's Video: Pulsed Rocket Drives
Scott Manley makes some excellent videos. This is a thought provoking one about several futuristic rocket engine concepts. Note in the video that many of the drives are pulsed. I'm wondering if there are any SF stories incorporating those ideas. I'm thinking of the ergonomics for the...- anorlunda
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- Rocket
- Replies: 4
- Forum: Sci-Fi Writing and World Building
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I Modeling a Bottle Rocket: Analyzing the Maximum Altitude
Edit: I've been catching errors I've made in the transcribing the formulas into latex ( not errors I made in the actual model..yet ). There may be more. I did this in one sitting. I've been trying to model a bottle rocket (water propellant, compressed air fuel) and my model seems ok for a... -
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A rocket on a spring, related to potential/kinetic energy
Part A) So from a force diagram we can see that the only two forces acting in our system are the spring force(positive y axis) and the weight of the rocket(negative y axis), which means the spring force is equal and opposite to the weight force. The weight is simple enough ##12* 9.8=117.6N##...- ChetBarkley
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- Conservation of energy Energy Kinetic energy Potential energy Rocket Spring
- Replies: 3
- Forum: Introductory Physics Homework Help
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Rocket ejecting mass in a direction perpendicular to its velocity
That was my approach: $$P_f - P_i = [(m-dm)(v + dv) + dm(u+v+dv)] - [m(v)]$$ $$= mdv - dmv + dmu + dmv = mdv + dmu = 0$$ Since the variation of the rocket's velocity is perpendicular to itself, $$ dv = v d \theta => m v d \theta + dm u = 0$$ So we have $$\frac{dm}{m} = \frac{-v d \theta}{u}$$...- LCSphysicist
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- Direction Mass Perpendicular Rocket Velocity
- Replies: 6
- Forum: Introductory Physics Homework Help
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Trouble with a Rocket Propulsion question (Variable Mass & Momentum)
I chose to set the upwards direction to be positive and dM/dt = R = 190 kg/s, so I can solve the problem in variable form and plug in. With the only external force being gravity, this gives M(t) * dv/dt = -M(t) * g + v_rel * R where M(t) is the remaining mass of the rocket. Rearranging this...- vparam
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- Differential equations Integals Mass Momentum Propulsion Rocket Rocket propulsion Variable mass
- Replies: 2
- Forum: Introductory Physics Homework Help
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Engineering Velocity Decay Curve for a Rocket
I am trying to solve the problem below. I have previously calculated from 0 to 4 seconds how far the rocket will travel in each second. I am stuck now as to how to start this problem. I have searched but unable to find the answer. Do i need to rearrange this? A is currently 14 which does not get...- pete321
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- Curve Decay Rocket Velocity
- Replies: 4
- Forum: Engineering and Comp Sci Homework Help
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Time dilation and length contraction for a rocket
Hi, It's not a homework but still thought to post it here as advised in the past. A rocket is going to leave Earth's surface and it is decided that a data pulse encoding emission time of pulse will be sent every second from Earth station to the rocket, and the rocket would do the same. The...- PainterGuy
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- Contraction Dilation Length Length contraction Rocket Time Time dilation
- Replies: 12
- Forum: Introductory Physics Homework Help