What is Terminal velocity: Definition and 224 Discussions

Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid (air is the most common example). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object. Since the net force on the object is zero, the object has zero acceleration.In fluid dynamics, an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving.As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will equal the gravitational pull on the object (buoyancy is considered below). At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster than the terminal velocity (for example because it was thrown downwards, it fell from a thinner part of the atmosphere, or it changed shape) will slow down until it reaches the terminal velocity. Drag depends on the projected area, here, the object's cross-section or silhouette in a horizontal plane. An object with a large projected area relative to its mass, such as a parachute, has a lower terminal velocity than one with a small projected area relative to its mass, such as a dart. In general, for the same shape and material, the terminal velocity of an object increases with size. This is because the downward force (weight) is proportional to the cube of the linear dimension, but the air resistance is approximately proportional to the cross-section area which increases only as the square of the linear dimension. For very small objects such as dust and mist, the terminal velocity is easily overcome by convection currents which prevent them from reaching the ground and hence they stay suspended in the air for indefinite periods. Air pollution and fog are examples of convection currents.

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  1. F

    Terminal Velocity Help: Solving for Upward Force and Fall Time

    terminal velocity help! Homework Statement ok here is the problem. i found parts (a) and (b), but don't know part c. You drop a single coffee filter of mass 1.8 grams from a very tall building, and it takes 45 seconds to reach the ground. In a small fraction of that time the coffee filter...
  2. C

    Terminal velocity for big objects

    Homework Statement The drag force on large objects such as cars, planes, and sky divers moving through air is more nearly Fdrag = -bv^2. For this quadratic dependence on v, determine a formula for the terminal velocity vTerm, of a vertically falling object. Express your answer in terms...
  3. R

    What is the terminal velocity of mass falling toward earth?

    Assume no atmosphere; no friction; no extraneous factors. What is the terminal velocity of a mass that falls from the edge of Earth's gravity well to Earth's surface? Thank you in advance for your answer. Peace rwj
  4. G

    What is the terminal velocity of a ping pong ball?

    1. How long does it take a ping pong ball to reach terminal velocity? 2. What is the terminal velocity of a ping pong ball?
  5. G

    Terminal velocity with an initial velocity?

    How could I find how long (time) it takes to reach terminal velocity with an initial velocity? http://www.geocities.com/operation_rising_star/mis.tve.htm <- does this make sense? using 1/2pV^2*C*A=ma Thanks in advance.
  6. J

    Terminal velocity when falling through the atmosphere

    Dear all, I have been working my way through the Oxford University physics test sample paper http://www.physics.ox.ac.uk/admissions/combined-sample.pdf" and I have come across this question: A sky-diver jumps out of an aeroplane. Which of the following statements is true after she reaches...
  7. C

    Gravity and Terminal Velocity: Understanding the Relationship

    Newbie question here, so sorry if it is silly to those in the know.. If a skydiver reaches his terminal velocity because the drag caused by air at height x, why isn't the gravity at x/2 strong enough to overcome the already reached terminal velocity? It seems to me that a falling object...
  8. C

    Terminal Velocity and Resistive Forces problem

    Homework Statement A sky diver of mass 81.5 kg jumps from a slow-moving aircraft and reaches a terminal speed of 50.0 m/s. (a) What is the acceleration of the sky diver when her speed is 30.0 m/s? Homework Equations mg = bv where b is the friction constant and v is the terminal velocityThe...
  9. P

    Terminal Velocity of a ping pong ball

    Homework Statement The Attempt at a Solution I'm at a complete loss here. Part A was simple enough, and I calculated a terminal velocity of 28 m/s for the ping pong ball and 34 m/s for the golf ball. But I don't even know how to begin Part B. Wikipedia says that Euler's Method is for...
  10. jinksys

    Graphing Terminal Velocity using Euler's Method

    Suppose an object of 20kg is shot upward with an initial velocity of 20m/s. The drag coefficient I've chosen is 0.25, and gravity is 9.8m/s. I'm trying to calculate the terminal velocity using Euler's Method (using a C prog), and then graph the data using openoffice. I know I am converging to...
  11. D

    Terminal Velocity & Parachutes

    I can't really follow the template with this question. Im dropping parachutes out of a window with weights attatched. I'm assuming that they travel at terminal velocity from the moment i drop them, and i know this becomes less and less true the heavier weights i use. I plotted the results...
  12. P

    How Long Does It Take a Raindrop to Reach 63% of Its Terminal Velocity?

    Homework Statement The terminal velocity of a 2×10−5 kg raindrop is about 7m/s. Assuming a drag force Fd= - bv, Assuming a drag force determine the time required for such a drop, starting from rest, to reach 63% of terminal velocity. Homework Equations Fd=-bv Sum of F-maThe Attempt at a...
  13. M

    Terminal velocity of a body of mass

    A small body of mass m located near the Earth’s surface falls from rest in the Earth's gravitational field. Acting on the body is a resistive force of magnitude kmv, where k is a constant and v is the speed of the body. a) Write the differential equation that represents Newton's second law...
  14. L

    Terminal velocity and drag force in one dimention

    In one dimensional cases, will the velocity of a particle tend to the terminal velocity unregardless of any combinations of forces? I try to investigate this equation: mv'+bv=F(t) Using the mathematics theorem at the botton, I found that v --> F(c)/m as t tends to infinity. (where c is some...
  15. L

    What is the Terminal Velocity of Cats?

    Thought this was funny and decided to share: http://ffden-2.phys.uaf.edu/211.web.stuff/Kuhns/terminal_velocity.htm
  16. R

    Question about exhaust velocity and terminal velocity

    I had made a model assuming a relativistic rocket accelerating with constant power,variable acceleration,variable total mass the result however is somehow counterintuitive. The less exhaust velocity the rocket have, the higher terminal velocity it will have. Is that means I did something wrong ?
  17. S

    Exploring Terminal Velocity: Can Objects Fall Faster than the Speed of Gravity?

    So, someone said the random quote "We dropped him faster than a magnet". So my question is, if this proposed magnet were attracted to the ground, could it go faster than terminal velocity? Or is terminal velocity the fastest something can fall?
  18. P

    Terminal velocity and g-forces

    Hi, I need a little help with my understanding of g-forces. From what I can gather, this "force" is the acceleration experienced by the object expressed as a multiple of g (the usual acceleration due to gravity). What has confused me, though, is the Wikipedia page, which says that "A...
  19. D

    Examining Terminal Velocity & Its Impact on Gyrocopter Descent

    So I have this literature review which is due in like two days about identifying the variables involved in my experiment which involves the descent of two paper gyrocopters- where one was slightly bigger than the other. I am identifying terminal velocity as a factor which affects the descent of...
  20. T

    Assistance with Vertical Terminal Velocity motion - What do you think?

    Homework Statement A parachutist is falling vertically with a uniform speed of 12 m/s. At the instant he is 50m above the ground, he drops a coin. (Ignore Air Resistance) A) What is the seed with which the coin strikes the ground? b) How long does it take for the coin to reach the ground...
  21. J

    Exploring Terminal Velocity of Aluminum Loop in Magnetic Field

    Homework Statement Verbatim from the book: A square loop is cut out of a thick sheet of aluminum. It is then placed so that the top portion is in a uniform magnetic field B, and allowed to fall under gravity. (In the diagram, shading indicates the field region; B points into the page.) If the...
  22. D

    Terminal Velocity Lab: Finding Constant C in Fdrag=Cv^N

    Homework Statement We did a lab that was about terminal velocity; we had to drop coffee filters from different heights, and we had to take down data. We were given a formula Fdrag=Cv^N where C is a constant, and N=1. I have no clue how to find the constant C, can someone help...
  23. S

    Terminal Velocity: Calculate Mass of 22cm Ball

    v^2= (4mg)/A so if a 22cm diameter ball has a terminal velocity of 85m/s, what would the mass of the ball be? A = 4pi r^2 22cm= 0.22m v^2 = (39.2m)/(4pi (.11)^2) 7225= (39.2m)/(pi*.0484) So I got 28kg for the mass and that is not right. Please help. Stephen Doty
  24. T

    Distance to reach terminal velocity experiment

    I am planning an experiment for my coursework in which i am dropping spheres of different mass and calculating their drag. They will be of different sizes, but are made of plastercine so are relatively light. I would guess the heaviest would weigh no more than 20 grams. Does anybody know...
  25. J

    Deriving and Integrating Terminal Velocity Equation for Position

    (dv_y)/(v_y+v_t) = (k/m)(dt) where v_y is y velocity, v_t is terminal velocity, k is fluid resistance constant, m is mass and t is time This is my equation I derived for terminal velocity. I am going to integrate it for a function for position. In my text, the limits of integration on the...
  26. H

    Can a rocket go faster than it's terminal velocity?

    Homework Statement u ---> gas speed (relative to the rocket) v ---> rocket speed (relative to the stars) v - u ---> speed of gas relative to the stars v - v_0 = u ln \frac{M_0}{M} Where M0 is the initial mass of the rocket, and M is the final mass. Part a) If a rocket...
  27. M

    Terminal Velocity of a sky diver

    Homework Statement A sky diver of mass 83.0 kg jumps from a slow-moving aircraft and reaches a terminal speed of 46.0 m/s. (a) What is the acceleration of the sky diver when her speed is 30.0 m/s? Homework Equations R=-bv mg-bv=ma The Attempt at a Solution since R is the...
  28. N

    Does Shape Affect Terminal Velocity?

    Before an object hit terminal velocity does the shape matter. In other words if you drop a small rectangle will it slow down in any way or will it keep on falling till it gets to it's terminal velocity. then another part to that is why when you drop a pencil or anything else shaped like that...
  29. P

    Did the Atomic Bomb Dropped on Hiroshima Reach Supersonic Speeds?

    Recently, the New York times ran the obituary of Paul Tibbets who was the pilot of the plane that dropped an atom bomb on Hiroshima. At one point the article says: "At 8:15 a.m. local time, the bomb known to its creators as Little Boy dropped free at an altitude of 31,000 feet...
  30. J

    Calculating Terminal Velocity in a Fluid

    Homework Statement A 1.5-mm-diameter steel ball bearing (7830 kg/m^3) is dropped into a tank of SAE 30 oil. What is its terminal velocity? The density of oil is 917kg/m^3, and the viscosity of oil is 0.26kg/(m*s). Help is much appreciated! Homework Equations Force of drag = 1/2 *...
  31. J

    Terminal Velocity Steel Ball Bearing in Oil

    A 1.5-mm-diameter steel ball bearing (7830 kg/m^3) is dropped into a tank of SAE 30 oil. What is its terminal velocity? The density of oil is 917kg/m^3, and the viscosity of oil is 0.26kg/(m*s). Help is much appreciated!
  32. S

    Question about Terminal Velocity and Net Force

    My physics teacher told my class that in order for there to movement, there must be a net force on an object. He also said that when an object reaches terminal velocity the Fnet is zero because air resistance equals that of the object's weight. Then, he said that the object continues to fall...
  33. S

    Terminal velocity in a viscous medium

    A 11.00 kg object starting from rest falls through a viscous medium and experiences a resistive force R = -bv, where v is the velocity of the object. The object reaches one half its terminal speed in 5.84 s. (a) Determine the terminal speed. 82.7 m/s (b) At what time is the speed of the object...
  34. R

    Terminal velocity of a coffee filter

    Homework Statement You drop a single coffee filter of mass 1.2 grams from a very tall building, and it takes 47 seconds to reach the ground. In a small fraction of that time the coffee filter reached terminal speed. (a) What was the upward force of the air resistance while the coffee...
  35. E

    Terminal Velocity Calculation: Air Density & Drag Coefficent

    Not a homework question as such, but I thought this was the best place to put it. I'm trying to work out the terminal velocity of a falling object, say myself (57kg) at 1000m, I have the equation from http://en.wikipedia.org/wiki/Terminal_velocity but have no idea what the drag coefficent is...
  36. Y

    Terminal Velocity of a Concrete Sphere

    Homework Statement I need to find the approximate terminal velocity of a baseball shaped concrete sphere and what distance it would take to reach that terminal velocity if dropped on Earth under normal weather conditions. I have found that a baseball made of concrete would have a mass of...
  37. J

    Terminal velocity with Reynods# and Drag Coeff.

    Hi guys I've been reading on the boards for a few days now and everyone here seems really helpful, so I've decided to come and ask for some guidence on a problem I've been having Homework Statement I have to find the terminal velocity of a smooth wooden ball. rho(ball)=420 kg/m^3...
  38. P

    Drag Force Equation Useless in Finding Terminal Velocity

    As most of you know, the drag force equation is Fd=1/2*p*Cd*V^2*Cd*Ac. At terminal velocity, Fd equals weight. If you find the value of all the variables except Cd and V, you still won't have anything. But the terminal velocity equation is Vt= sqrrt of 2weight/p*Cd*Ac. So if V is terminal...
  39. P

    Drag coefficient w/o terminal velocity

    I know the equation for terminal velocity and drag coefficient. But I can't find one without the other. It's a real catch-22. I also don't know the Drag Force. HEEELP!
  40. T

    Exploring B-Fields and Electrons: Terminal Velocity?

    This term we have been studying B-Fields (Magnetic Fields), Electromagnetic Induction and A.C. Theory (High School Physics). We've been given the Exam outline and upon checking what will be in Complex Reasoning (Part C of the Exam), it labelled "Terminal Velocity on conductors falling through...
  41. K

    Integration (terminal velocity)

    i have 4 equations that need to be integrated 1.) mg-kv-u=m*dv/dt 2.) mg-kv-u=m*v(dv/ds) 3.) mg-kv^2-u=m*dv/dt 4.) mg-kv^2-u=m*v(dv/ds) **if it helps... the values are m=3000 g=10 u= 172000 v changes so leave it as v any help is good help if those are...
  42. K

    Variable acceleration terminal velocity

    4 conditions - initial velocity = 1000 m/s - height from Earth = 100 km - total mass = 3000 kg - rocket capabilities (thrust) = 100 kg/s at MACH 5 i was told that to use viscous and laminar drag as two options and to keep mass constant (to simplify things a little). the spaceship is...
  43. B

    Terminal velocity of a lacrosse ball?

    Can anyone help me with the terminal velocity of a lacrosse ball? Approximations would help too. Thanks.
  44. M

    Terminal velocity and drag coefficient?

    Ok, I think I'm getting a hold on this problem, but I want to make sure I'm in the direction... Homework Statement Let \inline{v_\infty} be the terminal velocity of a falling body in air. If the body is dropped from rest, find the expression for the speed as a function of time (1) if the air...
  45. K

    What is the terminal velocity of a quarter?

    2 questions: What is the terminal velocity of a quarter? and How long does it take a quarter to accelerate to its terminal velocity?
  46. F

    Calculate the terminal velocity from a displacement-time graph?

    Hi Can someone please explain how I can calculate the terminal velocity from a displacement-time graph? I'm only finding solutions to velocity-time graphs, but that's not what I need. Thanks in advance.
  47. O

    Mythbusters Terminal Velocity Wind Tunnel

    Recreating the Mythbusters' Terminal Velocity Wind Tunnel - Need advice on Manometer Hello, I am trying to find the terminal velocity of a projectile. I am placing the projectile inside a clear tube and blowing compressed air inside the tube until the projectile is hovering at some height...
  48. R

    Terminal Velocity of Projectile

    Recently on an airsoft forum I took part in a discussion about the muzzle energy of airsoft guns, which turned into a discussion about the terminal velocity of a .25g BB. Now, I believe that if the muzzle energy of the gun permits, a BB can be launched at 1870fps. Afterwhich, the air acts as a...
  49. C

    Terminal velocity in finite time

    v^2 = \frac{mg}{k}(1 - e^{-2ky/m}) As t \rightarrow \infty and y \rightarrow \infty we see TV = \sqrt{mg/k} And below my book reads: "From actual experience we know that a raindrop reaches its limiting velocity in a finite and not an infinite amount of time. This is because other factors also...
  50. P

    How Is Terminal Velocity Calculated in a Magnetic Rail System?

    A bar of negligible resistance and mass of 17 kg is pulled horizontally across frictionless parallel rails, also of negligible resistance, by a massless string that passes over an ideal pulley and is attached to a suspended mass of 190 g. The uniform magnetic field has a magnitude of 600 mT, and...
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