Rocket Definition and 1000 Threads

Homework Statement A rocket launches from a space base at 0 velocity and looses mass at constant rate C. what is the ratio between the rocket's mass at maximum momentum to it's initial mass. Homework Equations Newton's second law: ##F=dP=\frac{d(mV)}{dt}## Conservation of momentum...

Homework Statement Rocket engine expends 1150 kg of gas in 1 second, with a velocity of -4.50×10^4 m/s. Calculate the average force exerted on the rocket by the gas during that 1.0 second interval Homework Equations F= m(delat)v / (delta)t The Attempt at a Solution F= (1150kg)(-45000m/s) / 1...

Homework Statement A rocket moving in space, far from all other objects, has a speed of 3.0 × 103 ms−1 relative to the Earth. Its engines are turned on, and fuel is ejected in a direction opposite to the rocket’s motion at a speed of 5.0 × 103 ms−1 relative to the rocket. What is the speed of...

Hi All, first time poster. I have a question about if there are any rockets people have built that can carry a 100kg payload into space? By 'people' i mean non commercial. Whats the best forum for this question? Thanks

when an object moves relative to something it experiences time at a slower rate right? now let's assume that an rocket moves 99.99% the speed of light, then what will be the rate of fuel consumption? will it remain the same or it will increase/decrease?

Ordinarily, combustion rockets and nuclear-electric rockets are considered as mutually exclusive categories. Would it be possible to have a launch vehicle engine which benefits from characteristics of both? For instance, chemical combustion generates a lot of kinetic energy from heat, and yet...

Homework Statement (a) Show ##a = \frac{a_0}{\gamma^3}##. (b) Find proper acceleration of rocket (c) Find speed as a function of time. (d) Find acceleration of second rocket. Homework EquationsThe Attempt at a Solution Part(a) 4-vector acceleration is given by ##\gamma^2 \left[...

Hello, A little something I've been working on for fun today was trying to derive the rocket equation: Δv=V_{e}ln(R) So first I start with F=ma =m\frac{dv}{dt} \frac{F}{m}dt = dv ∫_{0}^{Tco} \frac{F}{m}dt = ∫_{0}^{v} dv Where Tco is the time of engine cutoff, and v is the velocity at that...

No idea why this popped into my head on the drive home tonight, but here we go: Would it be possible to build a rocket filled with either liquid Nitrogen, or some other super-cooled substance, then use a battery of high-energy, ground-based laser beams pointed at the super-cooled propellant to...

An observer outside the rocket sees a light beam through a rocket that's accelerating. How will an observer inside the rocket see the light beam? (The problem is showed in the picture below) My friends and I had this problem at school today, and we couldn't decide which is right. Here are our...

1. Problem A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is a) 2 v b) (√2)v c) v d) v/2 e)...

I want to ask about the differences between a photon rocket and a rocket which uses conventional propellant. A conventional rocket shoots exhaust matter out the back end, resulting in impulse and acceleration. A photon rocket shoots photons out the back end, resulting in impulse and...

Lets say if i have a bell nozzle rocket engine such as this one : http://www.braeunig.us/space/pics/fig1-04.gif and inside the combustion chamber i have an average pressure of around 300 psi. If i wanted to feed in liquid fuel into it while the fuel pump is only able to supply 100 psi of fuel...

In space Hydrogen fuel is burned and propels the spaceship forward in the direction it's facing. Newton's third law of motion states that for every reaction there is an equal and opposite reaction. A lightning bolt makes around Five Billion Joules of energy. I can't find specific numbers for...

Apparently, this news is all over the net. NASA has given a Texas-based company called Ad Astra Rocket a 10 million dollar grant (the money will be given over a 3 year period) to help develop a functional VASIMR rocket (Variable Specific Impulse Magnetoplasma Rocket), which will supposedly take...

Homework Statement This is actually an Applied Project in the text, and overall is quite a large problem, so I won't post the entire thing, as there are lots of equations and steps where the text guides me by saying "show that...this thing...then...show that this other thing..." What I need...

Homework Statement Consider a cryogenic chemical propulsion system with Isp (specific impulse) = 450 s Enter the required propellant fraction as a proportion with at least two decimal places. The ΔVelocity is provided. ΔV = 9.6 km/s Homework Equations Rocket equation: ΔV = Vex x Ln (initial...

Homework Statement Hello was wondering what nose cone I should put on my rocket. We need to reach around 800ft, any higher/lower and points are deducted. I don't know whether to go with a rounded cone, parabola I've seen or a pointed cone... Homework EquationsThe Attempt at a Solution I know I...

I am writing a science fiction novel featuring a manned exploration into the Oort Cloud. So to keep things simple as possible, my question is this: is it reasonable to suppose an antimatter-powered spacecraft could travel from Earth space out to a distance of (say) 2,000 AU* within a...

Homework Statement A 1Kg rocket is fired off. The engine provides a thrust of 18 Newtons for 20 meters. What is the maximum height achieved by the rocket? Assume no loss of mass and no friction. Gravity=9.8m/s^2 Homework Equations Work=Force x distance Force=Mass x acceleration(or gravity)...

Hi PF, I'm working on a paper about rockets but I've come across something which confuses me. For my paper I calculated the fuel/mass ratios for several rockets, and found that their ratios vary quite significantly (assuming of course that I've done the calculation correctly). From my reading...

Hi I was wondering why are model rocket engines disposable after one use? Is it because it is more economically feasible to buy a new model rocket engine than to repair a used one because the process of using a model rocket engine always ruins it? Also, if it is the case that model rocket...

I am the kind of guy that always needs to return to the horse-and-carriage problem to hone in my understanding of Newton's Third Law. Here's my question. Assume a rocket in space is applying a force to another object of equal mass in space. Now, I understand the object in space is experiencing...

If your rocket is of a certain power range you need a certain license. My question is of you need these license's if you are only doing horizontal thrusts tests and never actually launching it vertically into the air?

Homework Statement A 15.0 g plastic water rocket containing 40.0 g of water and compressed air is strung on a very low friction horizontal wire. When fired, compressed air forces the water from the rocket in 0.600 s at an average exit velocity of 4.05 m/s [E]. Based on the information in the...

Homework Statement A rocket, initially at rest, propels itself in a straight line by giving portions of its mass a constant (backward) speed vout relative to its instantaneous rest frame. (a) Is rest mass conserved in this process? (b) Show that m0du′ = −dm0 vout, where m0 is the rocket’s...

Let's say we are on Earth-like planet, but without an athmosphere. There's a rocket on the ground and it's starting now. The rocket accelerates but at a point when it has enough speed it stops accelerating. The rocket has still enough speed to get further away from the planet but not enough to...

A rocket fires two engines simultaneously. One produces a thrust of 655N directly forward while the other gives a thrust of 508N at an angle 34.0∘ above the forward direction 1.Find the magnitude of the resultant force which these engines exert on the rocket. 2.Find the deviation of the...

Firstly, apologies if this is in the wrong thread. I'm currently writing a presentation on the physics of getting a spacecraft from Earth to Mars in the near future. In my research I've come up against Porkchop plots which seem to plot contours of equal characteristic energy so you can find...

I've formulated a method for modeling the flight of a rocket projectile. Can anyone read it over and point out any mistakes false assumptions, etc? thanks!

Homework Statement A rocket car is constrained to move on an elliptical track (semi-major axis a and semi-minor axis b ). The car is moving at a constant speed v_0 . Determine the acceleration of the car in \frac{m}{s^2} . a = 4 \hspace{2 mm} km , b = 2 \hspace{2 mm} km , and v_0 = 360...

Homework Statement I am trying to derive the formula for time varying thrust given that I know the initial mass/volume of water in a water rocket. Knowns will include initial pressure, initial volume of water, and nozzle cross sectional area. Homework Equations Bernoullis equation: (p/ρg) +...

I was wondering if there is a way to build a model rocket that has the capabilities to reach space (not go into orbit though). It would seem to be very difficult to reach space from the ground, but if you launch it from a balloon some 30 miles up, would it be possible, if not, any easier?

Homework Statement Suppose the rocket is coming in for a vertical landing at the surface of the earth. The captain adjusts the engine thrust so that rocket slows down at the rate of 2.40m/s2 . A 6.00-kg instrument is hanging by a vertical wire inside a space ship. I don't know if there are any...

I found a few questions on water rockets but am not able to understand the equations. The guide I am using has this for the exit velocity of the water: V = sqrt( ( 2 * pressure * nozzle_area ) / water_density ) I plug in the values for my water rocket to get V = sqrt( ( 2 * 17.24Newtons/cm2...

And how do I go about submitting a proposal of a new type of nosecone geometry I'm pretty sure has not been considered so far so that someone else may study it, test it, appraise it and write a paper on it? I just want someone more knowledgeable and smarter than myself (an complete layman in...

Greetings to everyone. I would like to ask how the shape of a rocket exhaust plume changes with distance, when the rocket operates in a vacuum. What I'm mainly looking for, is to see how large the diametre of the plume would be at a distance of ~20km from the nozzle. We're assuming an ordinary...

Hello loves, I know there are post very very similar to this, but I just needed some help understanding it. any help is truly appreciated. 1. Homework Statement A model rocket is launched straight upward with an initial speed of 50 m/s. It accelerates with a constant upward acceleration of 30...

I am trying to build a model rocket for a contest. It goes up as a rocket but comes down as a glider. Vertical takeoff. Does not jettison any parts. Should glide down in large slow graceful circles. Judged based on total hang time. I have been able to avoid a outright nose dive by putting the cp...

Homework Statement An astronaut went to sun from Earth by a rocket. According to the clock in the rocket, the traveling time was 5 minute. What was the velocity of the rocket? ( Earth is 8 light minute away from sun) Homework Equations t = \frac {t_0}{\sqrt {1 - \frac{v^2}{c^2}}}The Attempt at...

If an object say a rocket is thrown up in the sky with an additional acceleration say ' x ' , then why do we add the value of acceleration due to gravity i.e 9.8 m/s^2 to the acceleration ' x' in order to find the total acceleration... Since vector of acceleration due to gravity is directed...

http://www.reuters.com/article/2015/01/10/us-space-spacex-idUSKBN0KJ08120150110 Sniff sniff! A neologism, reland?

Homework Statement vertical rocket start: F_thrust (simple F) Δm (fuel consumed per Δt) m_tot the relative velocity of the gas w is demanded. Homework Equations vgas=v+Δv+w, w<0 m(t)=mtot-Δm*t The Attempt at a Solution rocket acceleration. F-G=m(t)*a(t) a(t)=F/m(t)-g first...

Homework Statement Small model rocketry engines are sized by specific impulse. One common size is a C6 engine. With each letter increase in engine size. The "C" engine is 10.0 N -s specific impulse. The "6" indicates that the engine produces an average thrust of 6 Newtons. How much time does...

Homework Statement The whole problem is in picture, but simply it says to find the max velocity of rocket, with those given units. The whole problem is worked out with pounds, but when I try to do it for meter and Newtons I get like 50 times bigger answer. The units : Total Impulse of motor...

So SpaceX is going to try to land a rocketship on a boat... That's pretty amazing, if you ask me. Does anyone know of a TV station that will be broadcasting the event live? I know I could watch it here http://www.spacex.com/webcast/ , but it would be nice to be able to see it on the big screen...

Homework Statement The problem and my attempt are attached Homework Equations Chain rule for partial differentiation perhaps And basic algebra The Attempt at a Solution I'm unsure of how to approach this but I differentiated all the expression at the top.

Homework Statement Earlier we considered a rocket fired in outer space where there is no air resistance and where gravity is negligible. Suppose instead that the rocket is accelerating vertically upward from rest on the Earth's surface. Continue to ignore air resistance and consider only that...

Homework Statement This is from chapter 1 (2nd edition) of Taylor and Wheeler's 'Spacetime Physics.' It's a four part problem, and I didn't have any troubles with parts a, b, or c. I'm stuck on part d. I'm supposed to determine if we could make it to Andromeda within a lifetime. Assume that...

Homework Statement A manned expedition is planned to be sent to Mars in 2023, one way. If the colony module was 100.0 tonnes in mass. Determine the work that must be done by the rockets to carry this colony from Earth to the surface of Mars. Homework Equations ET = PE +KE PE = -GmM/r KE =...