Skydiver
As a skydiver exits a plane, his downward velocity begins to accelerate.
1. What G-forces does he experience within the first few seconds.
2. At some point his velocity stablizes (if he is not twisting and turning, etc.), at that point what G force does he feel then?
Assume 1 G force is 9.8 meters per second per second = 32.2 feet per second per second even though we know that in reality, Earth's G-forces are reduces by altitude.
hjg
1. What G-forces does he experience within the first few seconds.
2. At some point his velocity stablizes (if he is not twisting and turning, etc.), at that point what G force does he feel then?
Assume 1 G force is 9.8 meters per second per second = 32.2 feet per second per second even though we know that in reality, Earth's G-forces are reduces by altitude.
hjg
Labels: SharedPuzzle
posted by Rajesh Lal at
7:58 PM
9 Comments:
Wont the G be constant (if height is not accounted for) the whole time. In the first few seconds it will be 9.8m/s*s and also till he touches the ground it will be 9.8 m/s*S again not accounting ff height is applied then the height will be needed.
Im not sure what is being asked could you elaborate?
The force would be reduced by wind resistance. Unless you assume the skydiver is jumping in a vacuum! :)
So, at the moment the skydiver leaves the plane, there is no vertical wind resistance. So, he accelerates towards the ground with 1 G. As his velocity increases, acceleration will decrease due to wind resistance. Eventually, gravity pulling him down will be balanced by wind resistance and his falling velocity will remain constant. At that time there is, in effect, 0 G acting upon him.
This will continue until he opens his parachute or hits the ground at his (truly) terminal velocity.
-HM
Neither previous answers are correct, maybe a hint will help.
g-force (also G-force, g-load) is a measurement of an object's acceleration expressed in gs. It is proportional to the reaction force that an object experiences as a result of this acceleration—or, more correctly, as a result of the net effect of this acceleration and the acceleration imparted by natural gravity. G-force is not, however, an absolute measurement of force and the term is considered a misnomer by some.
The g is a non-SI unit equal to the nominal acceleration of gravity on Earth at sea level (standard gravity), which is defined as 9.80665 m/s2 (32.174 ft/s2). The symbol g is properly written both lowercase and italic to distinguish it from the symbol G, the gravitational constant and g, the symbol for gram, a unit of mass, which is not italicized.
The unit g is sometimes written as "gee", and g-forces are informally referred to as "gees" (as in expressions such as "pulling ten gees").
hjg
wouldn't there be negative g's, considering we would be moving downward really really fast? until the wind resistance equals out anyway. so, idk about all that math, but you'd think there would negative g's
reply to previous
Negative gs? That would indicate a direction. While acceleration due to gravity is always down, I don't think G-forces are thought of as having a negative. When a jet pilot makes a sharp turn, his body is forced to accelerate from a straight line to a new path. The centrifugal force causes G-forces.
If he experiences 5 g's and he weighs 100 pounds, then the g-force would make him feel like he weighs 500 pounds. This would cause quite a load on his heart to pump blood. His pressurized jet suit puts pressure on his arms and legs to squeeze blood back into his head and trunk.
The jet's turn could be left, right, up or down, the g-forces
are still positive.
The original post asked two questions. The first is easy. When a skydiver first jumps, he is accelerating down as 9.8 meters per second^2, the same as the force of gravity because he is in "free-fall" just like the space walkers, he feels zero g's. At his point his heart has an easy job pumping blood, it does not have to pump against gravity. However just jumping out of a plane would be enough excitment to scare my heart into pounding double time anyway.
Can anyone figure out question two now?
hjg
Isn't the rate of freefall and G's constant until the shoot is deployed? Don't all objects fall at the same rate, regardless of mass?
When he first leaves the plane, he effectively weighs 0g because he's in freefall and accelerating at g. As he goes faster, air resistance slows him and he eventually reaches terminal velocity, at which point he will weigh 1g.
To Leslie,
Correct
1. zero g
2. 1 g
By the weigh (way) you can look up g-force on wikipedia and read about this. And in fact, you can find the info about the skydiver.
Congrats.
hjg
The Gravitational force is always 9.8m/s/s ... Velocity may change but force won't.
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