Notices
Results 1 to 10 of 10
Like Tree3Likes
  • 2 Post By GotAThirstFor
  • 1 Post By PumaMan

Thread: Exceeding Terminal Velocity

  1. #1 Exceeding Terminal Velocity 
    Forum Freshman
    Join Date
    Jul 2006
    Location
    Stevenage, UK
    Posts
    9
    This is a question that was put into my head watching the Superman movie trailer, so forgive the pretense!

    If an object falling to earth reaches its terminal velocity, is it possible for that velocity to be exceeded if a force is introduced that exerts on the object toward Earth... for the purposes of the pretense, lets say Superman is pushing an object that has reached terminal velocity toward earth. Can the object exceed terminal velocity due to this force?


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Isotope Zelos's Avatar
    Join Date
    Jun 2006
    Posts
    2,755
    yes, till it reaches the new termal velocity


    I am zelos. Destroyer of planets, exterminator of life, conquerer of worlds. I have come to rule this uiniverse. And there is nothing u pathetic biengs can do to stop me

    On the eighth day Zelos said: 'Let there be darkness,' and the light was never again seen.

    The king of posting
    Reply With Quote  
     

  4. #3  
    Forum Professor Zwolver's Avatar
    Join Date
    May 2006
    Location
    Netherlands
    Posts
    1,632
    Yes, terminal velocity does change if the eronvirement changes 2.

    The rock may also burn up or scatter due to it's high tv.
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
    Reply With Quote  
     

  5. #4 Re: Exceeding Terminal Velocity 
    Forum Freshman
    Join Date
    Jul 2006
    Location
    Kabul, Afghanistan
    Posts
    5
    Quote Originally Posted by thehumph
    This is a question that was put into my head watching the Superman movie trailer, so forgive the pretense!

    If an object falling to earth reaches its terminal velocity, is it possible for that velocity to be exceeded if a force is introduced that exerts on the object toward Earth... for the purposes of the pretense, lets say Superman is pushing an object that has reached terminal velocity toward earth. Can the object exceed terminal velocity due to this force?
    it's the air resistance that opposes a body's speed due to its weight, as the body gains speed the air resistance acting on the body increases, eventually the resistance equals the weight and no net force is acting on th body, now if some1 applies a force on the body on the downward direction, the body can be sayed to have greater weight with the same shape and volume and surface area, so now there is a net force acting downwards and causing the body to accelerate, Until ! the air resistance again equal its weight(the new weight),,,,,
    the answer, simply, is YES! it can exceed the terminal velocity.
    Dave Wilson and exchemist like this.
    All that is necessary for the triumph of evil is for good men to do nothing.
    Reply With Quote  
     

  6. #5  
    Forum Freshman
    Join Date
    Dec 2005
    Location
    India
    Posts
    65
    yes it can
    Reply With Quote  
     

  7. #6  
    New Member
    Join Date
    Mar 2014
    Posts
    1
    Superman, according to non scientific sources, has a type of aura barrier which extends around any relatively small objects, allowing the object to reach speeds greater than it's own terminal velocity but the highest speed that i know that Superman travels at which is approximately Mach 9
    Reply With Quote  
     

  8. #7  
    Forum Masters Degree
    Join Date
    Jan 2011
    Posts
    738
    exchemist likes this.
    Reply With Quote  
     

  9. #8  
    New Member
    Join Date
    Jul 2014
    Posts
    1
    No. Absolutely not! Superman's push is an increase in total external force applied--not a change in weight of the object.

    Weight is a determination of the affect of gravity against the mass of an object: W = M * g

    Weight and drag are forces which are vector quantities. The net external force F is then equal to the difference of the weight W and the drag D: F = W - D

    Drag increases with the square of velocity. When drag is equal to the weight, there is no net force on the object: F = D - W = 0

    Then: Cd (p * V / 2)^2 * A = W

    Where Cd = Drag Coefficient, p = gas density, V = velocity, & A = frontal area

    An object which is falling through the atmosphere is subjected to two external forces. One force is the gravitational force, expressed as the weight of the object. The other force is the air resistance, or drag of the object. If the mass of an object remains constant, the motion of the object can be described by Newton's second law of motion, force (F) equals mass (M) times acceleration (a): F = m * a
    which can be solved for the acceleration of the object in terms of the net external force and the mass of the object: a = F / m

    The acceleration of a falling object then becomes: a = (W - D) / m

    So as an object falls, we quickly reach conditions where the drag becomes equal to the weight, if the weight is small. When drag is equal to weight, there is no net external force on the object and the vertical acceleration goes to zero. With no acceleration, the object falls at a constant velocity as described by Newton's first law of motion. The constant vertical velocity is called the terminal velocity.

    Using algebra, we can determine the value of the terminal velocity. At terminal velocity: D = W; or Cd * r * V ^2 * A / 2 = W

    Solving for the vertical velocity, we obtain the equation: V = sqrt ( (2 * W) / (Cd * p * A).

    Conclusion: Superman's push will increase the ACCELERATION up to Terminal Velocity, but will NOT change the maximum speed. For Terminal Velocity to change, you must change the size and/or shape of the asteroid, altering the drag coefficient.

    HOWEVER, the terminal velocity with DECREASE as the asteroid falls, falling through progressively thicker atmosphere, increasing the gas density--causing it to actually slow down as it continues to fall, after it's reached Terminal Velocity.
    Reply With Quote  
     

  10. #9  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    951
    what waste of time
    Reply With Quote  
     

  11. #10  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    10,821
    Quote Originally Posted by Gawain_VIII View Post
    An object which is falling through the atmosphere is subjected to two external forces.
    And yet, as YOU posted:
    Superman's push is an increase in total external force applied
    I.e. it will go faster.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •