Posts Tagged ‘velocity’

Aerodynamics

Buoyant force concept and terminal velocity? My aerodynamics book(John Anderson Aerodynamics) say that whenever a body moves through a fluid, there are only two types of forces acting on the body. 1. Pressure force that acts perpendicular to the plane of the body and the other is the drag force that acts parallel to the objects velocity.

 

Forces at Work

 

Also i read an article that buoyant force is related to static fluids not moving fluids. Now, i was working on a concept of terminal velocity of an object moving through air in the Z direction. According to my concept, the air is continuously in motion and hence its a dynamic fluid. So, accordingly, the body falling through air will experience friction drag parallel to the velocity and pressure force perpendicular to the velocity. But as i was going through the derivation of the terminal velocity, they have counted the buoyant force in which is completely confusing me. If there is buoyant force when the body is moving through a moving fluid then when an aircraft is cruising at an altitude, why do they not mention the buoyant force? Rather they say that the vertical force is the pressure force which is also the lift force. I am really confused when to apply buoyancy and the concept of this pressure force which acts perpendicular to the plane of the body Please help me.

 

Comments - What do you think?  Posted by admin - February 20, 2013 at 9:41 pm

Categories: Ask Physics   Tags: , , , , , , ,

Questions waiting for answers here!

  • If energy is mass-less then why does it cause linear momentum?
  • one object is thrown upward with velocity v from height h and another object is thrown downward with same velocity v and other object is thrown horizontally with same velocity v. which of the above will get maximum speed while touching the ground?

Comments - What do you think?  Posted by admin - November 28, 2012 at 7:11 pm

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A Complicated problem from force and motion

A particle is at rest. A force F is continuously pushing it forward at all velocities it attains till infinite time say till n seconds where n tends to infinity find the final relation for velocity, force, energy etc .”

Prof. Shatendra SharmaOriginally shared by Shatendra Sharma Professor at Jawaharlal Nehru University

Do you know the solution? Post them as comment to this post.

Comments - What do you think?  Posted by admin - September 29, 2012 at 4:09 pm

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Angle between acceleration and velocity in projectile motion

What is the angle between the directions of  acceleration and velocity at the highest point of projectile?

Answer:

At the highest point of a projectile, the vertical component of velocity is zero and the velocity is entirely horizontal. The direction of acceleration (due to gravity) is vertically downwards throughout the motion of the projectile.

Therefore, the angle between the direction of acceleration and velocity at the highest point of a projectile is 90 °

Comments - What do you think?  Posted by admin - September 6, 2012 at 6:05 pm

Categories: Ask Physics, KINEMATICS, Problems   Tags: , , , , , , ,

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