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Name: Erika
Status: student
Age: 17
Location: N/A
Country: N/A
Date: 1999 


Question:
I need to know what's the average speed of an airplane while moving in air? And if its falling would it be falling at the gravitational velocity of 98m/s?


Replies:
Hello,

A commercial airplane travels at a velocity of about 600 miles per hours. This is just under 1000 km/hrs, or 16 km/min, or about 270 m/second.

Some airplanes travel much slower and some much faster.

9.8 m/second-squared is actually gravitational acceleration. It is the rate of change of VELOCITY, not velocity itself. When an object falls freely under the force of gravity, its velocity increases until it reaches an equilibrium value, known as the terminal velocity. At this velocity, the gravitational force (mass x acceleration) exerted on the body is exactly balanced by a drag force due to air resistance. This velocity remains almost constant to the end.

I do not know what the terminal velocity of an airplane is. I suppose it very much depends on the size and the shape of the aircraft. But I know that a person falling or parachuting out of an airplane (with the parachutes closed) has a free fall velocity of about 120 miles per hr or about 50 m/second.

I hope this helps.

Dr. Ali Khounsary
Advanced Photon Source
Argonne National Laboratory
Argonne, IL 60439


Cruising speeds for large commercial airplanes are always less than the speed of sound. The speed of sound varies depending on atmospheric conditions, but let us assume it is 1000 ft/sec which would then convert to 681 miles per hour. Maximum cruising speeds are a bit lower but the average duration of a flight from Frankfort, Germany to Chicago is around 9 hours (we are heading into the wind) the trip is around 4000 miles, hence the average speed for the entire voyage is 444 miles per hour.

I don't know what you mean by 98 meter/sec. The acceleration due to gravity is 9.8 m/sec/sec. A free falling object could have a considerably higher velocity depending on its shape.

H. Myron


Erika - This is kind of like asking the aveage speed of a car. It varies a lot depending on the car and the situation. Just a few thoughts:

Typical landing speed
Small general aviation aircraft (e.g. Cessna)
60 knots

Airliner 130 knots

Typical cruising speed
Small general aviation aircraft (e.g. Cessna)
120 knots

Airliner 500 knots

The Concord cruises at about 1400 knots and the Wright Brothers flew 120 feet in 12 seconds - 10 feet per second

And if its falling would it be falling at the gravitational velocity of 9.8m/s?

In free fall - without considering air resistance - it would fall at 9.8 m/s. In a power dive it could be much faster than this. Hope this helps.

Larry Krengel



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