Rockets Definition and 136 Threads

This might have been answered before but it's something that has been bothering me. A rocket in space will move in a straight line. If I apply thrust, it still moves in a straight line unless I apply the thrust in a different direction. So unless I have rocket nozzles attached to the side...

hi, everyone. something iv been pondering recently, is there a set speed at which something burns up in the air/atmosphere, or is it more to do with the surface area of the object traveling through the air, which would mean more of a drag force which means that the extra energy transforms to...

Homework Statement A truck hauling a big tank of oil starts at position x=D (Chicago) and heads due west (–x direction) toward its destination at x = 0 (Des Moines). At Chicago, the total mass of the loaded truck is M and the mass of oil it is carrying is λM. (Thus M(1–λ) is the "tare" mass =...

Homework Statement Two rockets are orbiting a Schwarzschild black hole of mass M, in a circular path at some location R in the equatorial plane θ=π/2. The first (rocket A) is orbiting with an angular velocity Ω=dΦ/dt and the second (rocket B) with -Ω (they orbit in opposite directions). Find...

Hi. I have recently been trying my hands at calculating a few orbits but have encountered difficulties in trying to 'understand' the semi latus rectum. P=h^2/GM What does it have to do with the orbiting object's angular momentum? How come I get different values when I derive it from other...

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...

Okay, first of all, I'm not very good at maths, so I will have to talk in programmer terms here. I have the following issue: A small rocket is moving in space, and I want it to move to and stay at a location in space, similar to a quadcopter. No as far as I see it, I have the following variables...

How do you calculate how much delta v is lost from gravity and atmospheric drag? I've been looking for days but I can't find anything that actually tells me how it's calculated. For example it takes 1.5 km/s - 2 km/s extra delta v for a low Earth orbit because of drag loss, how was that number...

I love doing water rockets and I normally do them in the regular physics classes. However, I would like to do a water rocket lab with added rigor for the AP level course. I was thinking about having them write a iterator to factor in the drag and try to predict apogee. That might be too much...

Whenever a rocket prepares for launch, they always release this white gaseous substance. Does anyone know what it is and the purpose releasing it? You can clearly see it in this video: https://www.youtube.com/watch?v=lbHnSu-DLR4&list=UUtI0Hodo5o5dUb67FeUjDeA...

Homework Statement A rocket moves upward, starting from rest with an acceleration of 29.4 m/s^2 for 4s. It runs out of fuel at the end of this 4s interval and continues to move upward. a.) how high does it rise from the ground? b.)When the rocket will hit the ground? The Attempt at a...

Homework Statement http://puu.sh/5nKxl.png Homework Equations α = ω/t τ = I*α The Attempt at a Solution CM = [232200*99 + 99/2*12500] / (107100 + 232200 + 12500) = 67.102 m τ = 43320*67.102 + 43320*(99 - 67.102) = 4288680 N α = ω/t τ = I*α τ = I*(ω/t) ω...

Hi guys, Wacky idea, Could we use a combination of balloons and spacecraft to place objects into orbit? A balloon could be used to attain altitude and reduce air resistance but the problem faced is that we need to reach a high velocity to escape the Earth's gravitational field. The...

The equation relating velocity of a rocket to it's mass is given by v1-v2 = uln(m1/m2), where v1, m1 and v2,m2 are masses and velocities at some times t1 and t2. Assuming a fuel mass to rocket mass ratio of 99 : 1, we get final velocity to be only 2.3 times the initial velocity. How then do...

I've just finished a course on Mechanics on my university and wish to apply that knowledge to learn more about rockets, missiles, firearms.. projectiles in general. Do you know any good book about the subject. How do missiles work? Why was the first ballistic missile ever invented only in WW2...

Really struggling with this one. In class we used velocity not speed for starters and had $m$ and $m+\delta t$. I can't figure out how to relate it to this question at all. If someone could point me in the right direction that would be great. A car is propelled by a rocket engine along a smooth...

The sun is far, far away. The Earth is far, far away. No stars. Nothing but unbounded spacetime. And three rockets. Rocket #1: Velocity (according to its odometer): 700 mph Towards Earth (constant speed) Rocket #2: Accelerating (according to its odometer) to 800mph towards some galaxy far away...

If a satellite tries to land on the moon without rockets to counter the force of gravity, it comes in too fast and crashes into the surface destroying itself. A satellite would be orbiting at approximately 1.8 km/s or so at a 50km altitude, and come in for landing from that height which would...

Homework Statement An asteroid 5 km in diameter and mass 3.3x10^14 kg had been discovered moving towards Earth at a speed of 20km/s and is 4 months away from direct contact. Lukily there are booster rockets parked in space and in a day or so one can be attached to the asteroid. What cpntinuous...

I'm looking for good intro texts involving astronautics and rockets. I found Understanding Space: An Introduction to Astronautics (https://www.amazon.com/dp/0077230302/?tag=pfamazon01-20), but from the table of contents, it doesn't look very technical. I'd like to find something technical...

How would I go about solving a problem like this? What would the answer be? Homework Statement Rockets A and B are fired straight upward from rest at the same time. Rocket A accelerates at 12.2 m/s2, while rocket B accelerates at 15.9 m/s2. Solve for the moment in time when the rockets are...

Homework Statement Could one expect to get a good thrust off oxygen and hydrogen fuel in a gaseous form, pumped at ~60 PSI into a 2 liter container? How much (in terms of mass) oxygen and hydrogen would be in the said container at such a pressure, assuming we have a 2/1 hydrogen/oxygen ratio in...

An example of what I mean: Suppose you had a blueprint for a chemical rocket. You build one, and it has mass m and provides thrust x. Suppose you scale the whole blueprint up by 1% and build another. The volume (and therefore the mass) of each part in the rocket has increased by a factor of...

hi i was wondering why rockets always start upright, as if they would start in a position parallel to the surface of the earth(or at least almost parallel to the earth, but at the equator this should not be such a problem, if there are no mountains or anything else close to the point where...

Hi. If two light clocks are put on a rocket at rest and then accelerated to relativistic velocities with one of the light clocks parallel to the direction of motion and one perpendicular, will one clock continue to measure the rate of change of time in the rest plane while the other one...

Homework Statement explain how relative velocity is related to the direction in which rockets are launched...

Homework Statement To get a flat, uniform cylindrical satellite spinning at the correct rate, engineers fire four tangential rockets as shown in the figure. (Picture is attached). If the satellite has a mass of 4800 kg and a radius of 2.7m , what is the required steady force of each rocket...

So... there came a question up in another board which I can't answer... and perhaps you can give me an answer. First of all there's the equation for kinetic energy: Ekin = 1/2 m v² Which effectively means that the amount of energy needed for constant acceleration rises lineary to the...

Ok, I am going to start this out by saying I know little about rocket engines, but I sure wish I knew more. When looking at things like specific impulse, thrust to weight ratio, actual exhaust velocity, etc; what type of rockets are the best choice/most used? Ie, solid, liquid bipropellant...

I'm interested in building a model rocket. Someone told me about water rockets and this looks pretty cool but are there any other guides or videos you can refer me to? I also have no experience in rocketry

Hey everyone, I'm in the process of designing a rocket that could achieve high(er) altitudes. Of course, I want to make the rocket as small as possible, but maximize the height. I understand that the Mass fraction of the craft should be 0.91, where 91%~ is fuel/propellant, 6%~ is payload, and 3%...

What will happen in the following scenario? I am standing on the earth. Right next to me, a small rocket containing a clock blasts off and accelerates to 90% of the speed of light almost instantly (within its 1st millimeter of travel). As the rocket passes my head, I look at its clock...

Homework Statement 1The rockets of the Goths and the Huns are each 1000 m long in their rest frames. The rockets pass each other, virtually touching, at a relative speed of 0.8c. The Huns have a laser cannon at the rear of the rocket that shoots a deadly laser beam at right angles to the...

I have 2 advantages of using rotational and orbital velocity of Earth in assisting easier rocket travel... 1. Uses less fuel as the rotational speed contributes to the rocket 2. Assists the rocket to easily produce the necessary escape velocity Are there anymore adv? I can't seem to...

Homework Statement A rockets course needs to be diverted by one degree. The mass of the rocket is 2000kg, and its forward velocity is 15000ms. The rocket has side rockets with a thrust of 25000N with which to effect course change. a) What is the rockets momentum after the course change...

Homework Statement Lights are placed at points A and B, which are 100m apart as measured in the rest frame of the earth. As a rocket moving at speed v = 3/5c, passes point A the light turns on. As the rocket passes point B, the second light turns on. As read on the rockets clock, the time...

Any one have any ideas or suggestions for beginner model rockets? I eventually want to make my own.

Homework Statement Explain the need to understand the law of conservation of momentum in the study of rocketry. (2marks) Homework Equations Sum of Initial momentum = sum of final momentum :) what two dot points would i need?

Two rockets are launched. Rocket A has a mass of 1656.4 kg and a velocity of 5.0 m/s at an angle of 15.9 degrees measured off of the positive horizontal axis. Rocket B has a mass of 1318.7 kg and a velocity of 960.8 m/s at an angle of 42.5 degrees measured off of the positive horizontal axis...

Homework Statement Far out in space, a mass1=146500.0 kg rocket and a mass2= 209500.0 kg rocket are docked at opposite ends of a motionless 70.0 m long connecting tunnel. The tunnel is rigid and has a mass of 10500.0 kg. The rockets start their engines simultaneously, each generating...

Hi all, I want to ask something with the fear of sound silly to most of you. A)Let's say we have two identical rockets and the air resistance is excluded. The first rocket travels upwards with 100mph while the second travels upwards with 50mph.It's obvious that after an hour the faster...

A refrigerator has coils in back that get hot, and heat is molecular motion. These moving molecules have both energy and momentum. Why doesn't the refrigerator need to be tied to the wall to keep it from recoiling from the momentum it loses out the back?

Nasa uses chemical rockets in space right? On Earth I could understand how they work, the one reaction produces an equal and opposite reaction. So on Earth the rocket would be pushing on air to propel itself. But there's no air in space... Edit:::: I added an s to "works" in the title, my bad

how can knowledge of distance moved by a rocket at any time,t be used in soft landing on a satelite?

What are the fundamental disadvantages to traditional rocket designs, such as the Ares (1 and 5), Saturn 5, Delta series, etc? So far I've come up with incompatibilities with existing airport infrastructure and a partial or total lack of reusibility (what parts are reusable need to be fished...

Physics please help with Motion of Two Rockets? Two toy rockets are traveling in the same direction (taken to be the x axis). A diagram is shown of a time-exposure image where a stroboscope has illuminated the rockets at the uniform time intervals indicated...

Firstly this is my first post on Physics Forums so hello to everyone. The question I have came about after experimenting with (soda pop) bottle rockets with my niece and nephew, and a certain video on youtube showing a Japanese guy strapped to a bunch of bottles (I estimate about 21, but it...

Why are rockets round? Why not triangular, would it not be easier to make in some ways?

Hi guys, I've got the following question : and he want's me to : I wrote the following code : I've solved part 1,2,4 .. but the problem is in part 3 which I don't understand what the question means (I tried by maximum and minimum the velocity and acceleration but I get the first time...

Homework Statement A satellite has a mass of 4000 kg, a radius of 4.9 m. 4 rockets tangentially mounted each add a mass of 220 kg, what is the required steady force of each rocket if the satellite is to reach 31 rpm in 5.1 min, starting from rest? Homework Equations \SigmaT=I...