Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system.
The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust.
Water jet comes from nozzle A=1m2, water speed is v=20m/s, density of water 1000km/m3, calculate thrust
Is it possible to find thrust from this data?
T=mass flow x v ?
= 20m/s x 1m2 x1000kg/m3 x 20m/s= 400 000N ?
Is more effective to use bigger nozzle A and slower water speed then use small...
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...
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...
Based on the little I know ion thrusters seem extremely impractical on earth, even because speeds over 20,000-30,000+km/h will result in immense friction and fire, so why not cut the high speed somehow and increase thrust which is abysmall? For example: the ions passing through a medium?? Wider...
When car drive uphill, gravity/weight has drag component, that is reason why you must add more throttle compare to ligther car at same constant speed uphill. So logicaly car increase fuel consumption.
But if you drive downhill, gravity/weight has thrust component, so your top speed("terminal...
So according to this if you need a force that can lift a human and even an extremely ultra-light craft (1500 N) and have a velocity of 200 m/s you can eject extremely small amount of fuel through the nozzle: 0.0007 or less kg per second for as long as you're using 15 MPa pressure which is doable...
Hi all,
I'm writing a technical manual for a starship in a science-fiction series I'm working on, I wanted to check with some folks here to make sure my calculations are correct concerning the ship's engine thrust.
The ship has a fully-loaded mass of 5 million metric tons. Using its...
In small sailing boat like optimist is well know technique when there is no wind, rudder pumping which push boat forward.You just need push-pull rudder left to right with fast movement.
1) Rudder is stiff(not flexibile like flippers for diving),so why rudder produce forward thrust if high and...
Been reading Rocket Propulsion Elements 9th Edition and got approval from my university to design a bi-propellant liquid fuel rocket engine for my senior design project, and I've been understanding everything so far but I haven't quite found an answer to how the pressure works throughout the...
If i wnat to lift/hover my self up 30ft off the groud (i am 110 pounds) how much HP would i need and how much would i need to lift/hover 300 pounds. Please answer TYSM
I was reading propulsion chapter 9 of Anderson's Flight book (http://213.230.96.51:8090/files/ebooks/Muhandislik/Anderson J.D. Introduction to flight (8ed., MGH, 2016)(ISBN 9780078027673)(O)(929s) EAs .pdf) and came to Figure 9.18 b) & c), Figure 9.19 (I cannot post the image here due to...
Hello!
I have recently found this fascinating article: https://zenodo.org/record/3596173#.YJ1ttV0o99B
The author claims that classical equation for rocket thrust in incorrect because F is not equal to ma for a changing mass.
Neither my professors nor me can see any errors.
Do you think this...
Hello,
I am doing some contact mechanics and I had an example in my Lecture notes about a simple thrust bearing with three balls where the bottom plate is stationary, the top plate rotates with angular velocity w, and the cage rotates with angular speed Ω.
It says by inspection Ω =w/2 but I...
I'm writing a simulation software for the Apollo 11 missions, I'm not allowed to mention my website because of forum rules but you can see it in my profile.
I am trying to now implement the RCS systems into the LM. The LM is the lander such as the one called "The Eagle" in Apollo 11. What I...
Hi everyone. I am tasked with making an EDF rocket for a university project. The end of the rocket has a set of flaps that redirect air to control the rockets trajectory, seen in the image. The 90mm EDF itself is located near region 1.. I would like to know why, the physics behind it, a smaller...
Let me start off by saying I decided to post this in the aerospace engineering thread because it directly deals with thrust, even though it is not for a plane or similar.
I have two equations that I can use to calculate the force on a baffle of a muzzle brake, Equation 1, from The Engineering...
What is wrong with saying that since the speed of fuel goes from 0 to -313m/s (rel to ground) in 1s, then its acceleration is -313m/s^2. This leads to wrong answer according to author's solution but I don't see why.
Hello all friends,
My questions about the these two types of bearings. I know that what is purpose of usage. But I don't know where can I use them. If someone knows information about that, please inform me.
Thanks you all.
The author of my textbook writes that a spacecraft 's "thrust in the radial direction at perigee changes the energy but not the angular momentum". Such a thrust increases the eccentricity of the elliptical orbit of the spacecraft because ##\epsilon \equiv \sqrt{1+2EL^2/\mu C^2}##, where...
Hello,
We know that most celestial objects in our solar system are in the equatorial plane of the sun. So too, does most of our spacecraft orbit in this plane as it explores our solar system.
For a spacecraft already traveling away from the sun and towards the outer solar system, how hard...
This is a conceptual problem. Consider two identical rocket ships in a gravitational field with no atmosphere. Ship A is hovering at a fixed altitude, ship B is ascending at a constant vertical velocity. Since neither ship is accelerating vertically, the thrust required of both should be the...
Why do vacuum rocket engine always producing high thrust than sea level rocket engine ?
for example spacex's merlin vacuum engine produce more thrust than merlin sea level engine. And it is due to the big nozzle with large area in vacuum engine because when the flow reaches mach 1 in the throat...
Hi All,
I'm trying to get a better understanding of the momentum thrust given by an over-expanded rocket nozzle (I realize this case voids the isentropic flow assumption used for the 1D isentropic gas expansion equations typically used for rocket engine design since the normal shock is not an...
(this problem is slightly modified from the original problem.)
There is a contact force(friction and normal force) between the wedge and the walls of the container and there is a fluid thrust acting on the side of the wedge in contact with the fluid( this force is normal to the slanted surface...
I think i read somewhere that jet engine shaft is neutral,because
forces at turbine and compressor
cancle out,so that mean axial berings don't have force on it in direction of thrust!?
(this can't be true,becsue in that case thrust will be zero...)
But if this is true ,against what pressure...
The Blackbird wind powered car travels directly downwind faster than the wind speed powering it. Typically a 10 mph wind from directly behind it will cause it to travel at about 30mph.
I am trying to analyse how the car accelerates from rest. I know how it travels faster than the wind speed so...
"Collection of Problems of Mechanics" by Meshcherskii.I see how the answer could be arrived at because each successive drag increases the number of ropes that must be used, but what I don't understand is why the thrust and drag of the tug doesn't play a role in the number of ropes required.
If I have a motor that is turning a shaft with only a small torque required but the shaft is also being forced into the motor, axially at a large force, what is the effect on the motor here?
If Faxial is large, does this effect T and how does this effect the motor?
I would like to know what is the current consensus on the effect of the position of the wing relative to a tractive propeller disc's uniformity of thrust (the focus configuration would be WWII fighters).
Assume a jet boat or personal water craft (JetSki, etc) has a movable propulsion nozzle. This nozzle can be moved vertically so that the water jet driving the boat forward can be either above the surface or below the surface of the water.
Further clarification. You are speeding along on your...
Hello all!
I have a mathematical question for you. I'm trying to design a thrust bearing that can withstand axial and moment loads. I've added a picture of a similar design. The design consists of two rings (grey) and sliding pads (blue) fixed on the bottom ring. The top ring slides over the...
I'm trying to determine the force needed for one object to displace another object underwater. Specifically, Object A strikes Object B hard enough to jettison it from the seafloor up to sea level/land, let's say the Pacific coastline. I have a timeframe in mind, density & mass of the two...
I'd like to design a ducted fan capable of generating 800 N of thrust. Though I can do fairly high level math, I just really don't even know where to start in calculating (or at least relatively accurately estimating the thrust generated by a propeller, particularly a ducted one (as I understand...
Hi!
I have had this question for ages, nearly impossible to find anything on the web. My experiments confused me even further! Its concerning the blockage effects of surfaces ahead of a propeller. For example let's consider the usual dual vectoring propellers on the sides of airshipcars like...
Hello.
Not sure how to even begin with this question honestly. Didn't learn anything about thrust regarding this topic so it got me dumbfounded.
Here's how I try to interpret it:
I'm assuming that the thrust created by propellers = net force of the ship, where I can use F=ma to find...
I have a frame which supports a crank rotating through 360°. The crank lifts a 30 kg weight 540 times a minute ( 540 rpm). As the crank moves 0° to 90° the weight is accelerated to full speed which means it has thrust but then from 90° to 180° it is slowed to a stop then from 180° to 270° it is...
I feel there is a really obvious flaw in my logic but i can't pin it down
So i have to find the thrust on the lamina which is basically force of bauyancy
F(bouyancy)= Vρg
Now volume of the triangular lamina is its rea into its hieght.
v = Ah
hence
F = Ahρgsome information i feel i didnt take...
if the first stage provides a thrust of 6.05 mega-Newtons [MN] and the space shuttle has a mass of 4,520,000 pound-mass [lb Subscript m], what is the acceleration of the spacecraft in miles per hour squared [mi divided by h squared]?
Equation: F=ma
conversions:
1000m=0.621mi
3600s=1 hour
I'm...
Homework Statement
I'm getting stuck with this one and in need of some direction! Obviously I'm not looking for a direct solution, but maybe a outline of what I should be doing? (I'll attach an image in a few minutes)
<Image here incoming!>
Known data:
d2 = d1 / 2
F = thrust force (N)
Pa = ρ...
Homework Statement
A vertical retaining gate 2metres X 24metres hinged about the bottom edge of a dry dock has water to a depth of 21 metres on one side. Calculate the Retaining Force at the middle of the free upper edge of the gate to keep it shut in the vertical position. With the density of...
Homework Statement
How can we determine the thrust/ propulsive force generated?
We know that:
There is C02 inside a given Volume V and we know the mass M of the gas inside the volume. We know that we release the gas from a hole of diameter 1.6 mm.
Homework Equations
PV=nRT
∑F= dp/dt
∫u(t)...
The picture above has thrust density as a column and I am not too sure what that is. Can anyone explain to me what the difference between thrust and thrust density? Thank you for your answers!
I read that a thrust augmentor can significantly increase the efficiency of a jet engine (http://www.pulse-jets.com/phpbb3/viewtopic.php?t=931). Now from my understanding, the thrust agumentor is sort of like a ramjet. Only, in this case, the cold air is being sucked in along with the hot air...
Hello, all -
A question has come back to tickle my brain.
Could a vehicle with less than 1G of thrust manage to escape the Earth's gravity well?
I'm thinking something like Space X's Falcon 9. As it landed, with just a little more thrust, it could go back up again, I would guess. So, if it...
Hi,
I am currently studying aviation engine outputs and to make my study linear in comparative analysis with standard Automotive engines I need some expert help.
Can anyone help me drive precise equations to convert:
1. Engine thrust in Kilo Newton into Horse Power and Watts
2. Engine thrust in...
[Moderator's note: This thread was created by moving posts from another thread, hence no homework template]
The name "centre of pressure (COP)" indicates representative pressure will act through this point for a vertical plane inside liquid.
If so, then total thrust= vertical area of the plane...
Let's say we have a tank with 1000 psi pushing in all directions, if we remove one square inch from an end, now the tank has 1000 psi more at one end than the other. Does this mean that there is a 1000 lb push in the opposite direction of the removed square inch?