Rocket Definition and 1000 Threads

Suppose man is traveling in a rocket. if rocket goes up, man feels someone thrusting him down, vice versa. What exactly pulling the man up/down in rocket?

I tried the second rocket equation vf = vi + v rel * ln(Mi/Mf) but it gives out approximately 4900 m/s for the answer but the answer is 4160 m/s

Fluid can exert force to object(move object) only through pressure and tangential stress caused by viscosity. if we look at balloon rocket ,here is Newton 3 law action-reaction,but this 3 law as usual don't tell nothing how fluid really exert force to the ballon.. it exert through pressure...

When calculating the dV available from a rocket booster, the below calculation is used: (ISP . g) . ln(Mass when full/Mass when empty) Is 'g' always equal to 9.81 in this equation, or do you use the actual gravitational acceleration that the booster will experience, at it's given altitude, to...

Since they started this I have been somewhat amazed by the ability to not only launch but also peacefully get back a rocket intact and landing on it's vertical axis. I'll admit I haven't read a ton of material with regards to this so pardon if this has been asked already. To me it seems that...

This isn't right, is it? -\dfrac{GM}{R}+\dfrac12 v^2=-\dfrac{GM}{R+h} v=\sqrt{\dfrac{GM}{R}}\left( 1-\sqrt{\dfrac{R}{R+h}}\right) He's doing energy conservation. The mechanical energy at the Earth's surface is equal to the energy when the speed is 0.

a dusty plasma design : https://www.nasa.gov/pdf/718391main_Werka_2011_PhI_FFRE.pdf has nuclear fuel held in place by electromagnetic fields. It uses a very massive moderator around the fuel to slow and reflect neutrons back to the fuel, to enable continued fission. But, there is one kind of...

Since initally the rocket at rest I wrote $$\vec{p}^R_i = (m_0, 0,0,0)$$ and at final situation $$\vec{p}^R_f = [m_0-\varepsilon m_0 N](\gamma, v\gamma, 0 ,0)$$ $$\vec{p}^F_f = [\varepsilon m_0 N](\gamma', -u\gamma', 0 ,0)$$ After equating them I get $$1 = \gamma - \varepsilon N\gamma +...

Hello, First of all, I hope this post is in the right section (aerospace engineering). I am doing research on the injector plate design for a hybrid rocket and I'm no where at the moment. I was thinking that I could improve the geometry of the injector plate in order to help improve some...

If we are in a cabine in a gravitational field and inside, we have a racket and a ball. We put strings in each side of the racket and we connect the racket to the ceiling of the cabine. This strings only allows us to keep the weight of the racket. Then, we drop a ball to the racket. We do this...

Let me preface this by saying I have no background in physics or any of the above other than hours and hours of reading. Could someone explain why (if a method was developed) we couldn't use EFA as a thrust system for a rocket? My reasoning is instead of using fuel to fight gravity and push...

Show that, according to relativistic physics, the final velocity ##v## of a rocket accelerated by its rocket motor in empty space is given by ##\frac{M_i}{M} = \Big ( \frac{c+v}{c-v} \Big) ^ \frac{c}{2 v_{ex}}## where ##M_i## is the initial mass of the rocket at launch (including the fuel)...

The first part I can answer. However, the answer to the second one differs from the one in the answer sheet. 1) The rocket first travels gaining speed (a=40m/s^2) and then after the fuel burns loses speed due to g=9.8 m/s^2. Thus, Hmax= h1 (traveled with a=40) + h2 (traveled with -a=g=9.8)...

This is not a spaceflight based forum, so I do not expect all to be familiar with Zubrin's nuclear saltwater rocket concept. Basically a rocket that uses plutonium or uranium salts in water to start a nuclear chain reaction which is supposed to happen somehow outside the engine (as it is getting...

In this paper by Carlip, a comparison is made between electromagnetic and gravitational aberration. For the latter case, he takes as a study subject the Kinnersley’s “photon rocket”, an exact solution which is known to have the strange property of not producing any gravitational waves, even...

we are asked to find u and v. I thought by listing the known I can proceed to solve the question, but got no idea where I should start solving the question from. [Moderator's note: Moved from a technical forum and thus no template.]

I am no expert, so forgive me if I sound rather ignorant, but I'm curious about this: are typical automobile fuels like gasoline, diesel and ethanol more energetic than, specifically, *chemical* rocket fuels [like perhaps the types used in missiles, space-bound rockets and such] if measured by...

So I've derived the rocket equation in empty space and with constant gravity. Now I am interested in adding air resistance. I'm aware that there are 2 different models as if 0<Re<1 then F_drag=k*v and if 1000<Re<30000 then F_drag=1/2*A*rho*CD*v^2. And for my purpose the second model is most...

So I'm playing around with some water rockets and I'm trying to figure out how fast the exhaust velocity of the water is. I've had an experimental approach using high fps camera to record and analyse (using tracker) the exhaust velocity. I'm using a 0,5 l soda bottle with 0,085 L ; 0,135 ; L...

Hello, my name is Marcos, I have a bachelor in advertising and public relations, and my hobby is maths and physics The equation of variable-mass motion is written as ##\mathbf{F}_{ext}+\mathbf{v}_{rel}\dfrac{dm}{dt}=m\dfrac{d\mathbf{v}}{dt}## There are different derivations for the equation...

The first way to solve this is to just say, by conservation of momentum, that M_{0}v_{0}=(M_{0}+Apx)\frac{v_0}{2} where Apx is the mass of dust the rocket comes into contact with in a distance x. For the second method, by considering the change of momentum of the dust in 1 second, we know the...

I must confess, I have no clue what to do

I'm pondering the behavior and persistence of rocket exhaust plume molecules far above the atmosphere. For example, the plume from an apogee circularization thrust from GTO (Geosynchronous Transfer Orbit) to GEO (Geosynchronous orbit). CO₂ and H₂O are among the molecular species emitted by a...

First, create a rocket ship with: * a clock * a 3-axis accelerometer * a computer * a 3-axis external thruster The rocketeer begins in Earth orbit and sets the clock to Earth time. Then the ship takes off on a random trip through our universe. The pilot will arbitrarily point and apply the...

1. A CO2 canister with the following dimensions will be used. 2. A shell was designed to house the CO2 canister, and the coefficient of drag was calculated to be 0.33 3. The constant thrust required to move the torpedo at approximately 1ft/s was found by using a free body diagram to generate...

I am using the derivative of momentum (dp/dt) with Newton’s 3rd Law with the gravitational force of Earth. F - [Force of gravity on rocket] = dp/dt F - (G * m_e * m_r / r2 ) = v * dm/dt + ma F = Force created by fuel (at time t) G = Gravitational Constant m_e = Mass of Earth m_r = Mass of...

In 2009, the same society together with the Tau Zero Foundation announced Project Icarus, a similar spacecraft that could achieve 15% the speed of light. That year, a physicist called Friedwardt Winterberg announced a fusion spacecraft that could be used as a capacitor to produce proton...

Radiation pressure that light provides is weak. The photon rocket only gives thrust on par with rockets if you are willing to exhaust way more energy than normally used for rocketry (antimatter/matter annihilation). By that time your exhaust beam will be loaded with enough photons to nuke...

I have been researching the rocket pendulum fallacy and have gotten into some spirited debate on the subject. If I understand correctly... 1. if the thrust is perfectly in line with the centerline (and no outside forces act on the craft other than gravity) it does not matter where the source...

Homework Statement: Your job is to determine when the lunar lander should fire its rocket to reduce its landing speed to below 5m/s for a safe landing. The lander will descend to the moon from an orbit 1000 meters above the surface of the moon (acceleration = 1.625 m/s^2). To avoid crashing...

I feel ok that in our atmosphere there is pressure that is a force to push against. But in a "vacuum" there is very little element available to push off of. I had some experience with near space high vacuum here on earth. The machinery was able to get down to analysis of element composition of...

21.1*50=1055 1055m/s is the velocity when the engine fails. I don’t know what the time should be in the second equation.

https://www.abc.net.au/news/2019-08-09/russian-rocket-explosion-kills-two-sparks-radiation-concerns/11398604 Radiation has been released following a Russian rocket explosion at the Nyonoksa naval ballistic missile test site. Part of the White Sea has been closed. 5 people now reported killed...

Is the gravity sling possible without rocket propulsion which dynamically guides the object to the right point? Ie, if instead of using a rocket, you shoot the object with an accurately aimed cannon from the moon, will it either hit the planet or miss it but never get slung/accelerated...

In the book by Tipler & Mosca, the section on F=ma for variable mass derives the following equation: ##\mathbf{F}_{ext}+\frac{dM}{dt} \mathbf{v}_{rel}=M\frac{d\mathbf{v}}{dt}## where ##\mathbf{F}_ext## is the external force on the system as a whole (ie not just the variable mass sub-system...

Could anyone kindly kind me as to where this formula is derived from and how, because I searched and can't find it anywhere

Hello everybody! I hope you are all doing well. I built a liquid rocket injector and the following feed system: I started to do hydro-static tests (cold flows) and a program I wrote records all the data for me (except for the flow rates which I measured experimentally by collecting the water...

I thought it is because of the consevation of the energy, so I used (gravitational potential energy at the top = elastic potential energy). Since the mass of the rocket never changes, I supposed mass= 1kg, and k value is unknown. As a result, I got the result that k value is decreasing as...

Ggg

we all know escape velocity is a velocity in which a body can escape orbit around the Earth and fly off into space. this needs to happen in space our just out of our atmosphere, due to drag that could bring an object back into orbit and cause it's velocity to degrade to a point where it would...

When a rocket engine exhausts into Space what happens to the particles or molecules that are thrown out? My interest is firstly where do they go e.g.: orbit the Earth or other planetary body if from a shuttle, orbit the Sun if ejected outside the capturing influence of a planetary body, or just...

Homework Statement While solving equation of rocket motion with Newton's law in 1-d,I pondered to apply Lagrangian method on this. However, I didn't get correct result. Because I can eliminate last 2nd equation using last equation and get some other equation which is certainly not rockets...

Homework Statement A fireworks rocket is moving at a speed of 45.0 m/s. The rocket suddenly breaks into two pieces of equal mass, which fly off with velocities v1 and v2. What are the magnitudes of v1 and v2? Homework Equations Conservation of Momentum m1v1 + m2v2 = m1vo1 + m2vo2 The...

https://www.cockcroft.ac.uk/wp-content/uploads/2015/10/gratus_RelWorksheet.pdf Refer to diagram at top page 8 showing light signal reflected (Event A) back to rocket (Event C) on t'.axis. If the space axis x' were drawn showing the position of rocket when the light signal was returned from...

Homework Statement A person in a rocket traveling at 1/2 c. There is a flash originated from the middle of the rocket. From his point of view, will the flash arrive at the front or the back of the rocket first or arrive at same time? Homework Equations Not sure The Attempt at a Solution Since...

Homework Statement Hi, I'm trying to calculate the formula for the position vs. time of a rocket landing from an altitude of 100km. I'm neglecting a lot of forces for simplification but basically, I want to solve ##F_{net} = Drag - mg##. Homework Equations Drag Force: D = ## \frac {C_dAρv^2}...

A while back I posted a black hole horizon puzzle. This is another puzzle in the same general spirit. It is based on the scenario described in this old PF thread: https://www.physicsforums.com/threads/a-flaw-of-general-relativity.115418/ Needless to say, as was the case with my previous...

Say there is a circular fence that has a diameter of 10 meters, and a rocket ship that is normally 20 meters goes very quickly so that its relativistic length is 1m from the position of an observer standing at rest with relation to the fence. The rocket ship starts to go in a circle inside the...