Forces acting on a sky-diver during skydiving

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In summary, the conversation discusses the labeling of forces in diagrams of a skydiver. The question is to label the forces as more than 700N, 700N, or less than 700N. The downward force, which represents the skydiver's weight, is always 700N. The upward force changes depending on the skydiver's speed and acceleration. The conversation clarifies the correct labeling of the forces and discusses the understanding of the relationship between weight, force, and acceleration.
  • #1
AlfieD
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ImageUploadedByPhysics Forums1385942442.549914.jpg
This is really simple but seems to be confusing me (mainly the third diagram in the picture). The question is to label ALL the forces (arrows) in ALL the diagrams with either 700N, more than 700N, or less than 700N. It should be noted that the sky-diver weighs 700N. My answers that you can see were me misreading the question and I think I was calculating his weight. Given a proper read of the question, mg new answers would be (from top arrow to bottom arrow): more than 700N, 700N, 700N, not sure (third diagram 1st arrow), not sure (2nd), 700N, 700N.

Thanks in advance, sorry for the incompetency.
 
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  • #2
Given a proper read of the question, mg new answers would be (from top arrow to bottom arrow): more than 700N, 700N, 700N, not sure (third diagram 1st arrow), not sure (2nd), 700N, 700N.


OK - let's make sure I understand you.

Diagram 1 shows one arrow pointing down as the skydiver starts out on the jump.
You say this is "more than 700N"

Diagram 2 shows two arrows as the skydiver reaches constant speed.
Your answer: 700N up, 700N down.

Diagram 3 shows two arrows as the skydiver's shute first opens.
Your answer is "not sure" up and "not sure" down.

Diagram 4 shows two arrows as the skydiver reaches constant speed.
Your answer is 700N both ways.

To check your answers, consider:
... where does the downward force come from in each case?
... is the skydiver accelerating, decelerating, or traveling at a constant speed, as he falls?

Complete the following sentenses by placing the words "bigger than", "smaller than", or, "the same size as" in the space provided:

If accelerating, then the up arrow is _______ than the down arrow.
If decelerating, then the up arrow is _______ than the down arrow.
If constant speed, then the then the up arrow is _______ than the down arrow.
 
  • #3
1) Smaller than
2) Bigger than
3) The same size as

?

So would my new answers be right. If so, were the forces for the third diagram (which I was unsure of), bigger than 700N (up arrow), and then smaller than 700 N (down arrow)?
 
  • #4
1,2,3 are correct.

were the forces for the third diagram (which I was unsure of), bigger than 700N (up arrow), and then smaller than 700 N (down arrow)?
Please answer this question:
me said:
...where does the downward force come from in each case?
It has a special name - what is it called?
 
  • #5
The diver's weight.

Thanks, I get it now.
 
  • #6
Well done :)

For people who google here later and are still confused:
The downwards arrow in each diagrams does not change length.
Only the upwards arrow changes.

downwards force W: W=700N in all the pictures.
upwards force F: F=W for constant falling speed, F>W when decelerating, and F<W when accelerating.

the free body diagram should give you W-F=ma for positive downwards.
the question is testing your understanding of this relationship.
 

What are the forces acting on a sky-diver during skydiving?

There are four main forces acting on a sky-diver during skydiving: gravity, air resistance, lift, and drag. Gravity is the downward force that pulls the sky-diver towards the earth. Air resistance, also known as drag, is the resistance that air particles create as the sky-diver moves through the air. Lift is the upward force that is created when air flows over the shape of the sky-diver's body.

How does gravity affect a sky-diver during skydiving?

Gravity is the most significant force acting on a sky-diver during skydiving. It pulls the sky-diver towards the earth, causing them to accelerate towards the ground. The force of gravity also determines the speed at which the sky-diver falls, known as the terminal velocity.

What is air resistance and how does it impact skydiving?

Air resistance, also known as drag, is the force that opposes the motion of a sky-diver as they fall through the air. As the sky-diver's speed increases, so does the force of air resistance. This force eventually balances out the force of gravity, causing the sky-diver to reach a constant speed known as terminal velocity.

What is lift and how does it affect a sky-diver during skydiving?

Lift is the upward force that is created when air flows over the shape of the sky-diver's body. This force helps to counteract the force of gravity, allowing the sky-diver to glide through the air. The shape and position of the sky-diver's body can affect the amount of lift generated.

How do the forces acting on a sky-diver change during different stages of skydiving?

During different stages of skydiving, the forces acting on a sky-diver may vary. At the beginning of the jump, the force of gravity is the most significant, causing the sky-diver to accelerate towards the ground. As the sky-diver reaches terminal velocity, the force of air resistance becomes equal to the force of gravity, resulting in a constant speed. When the parachute is deployed, the force of lift increases, allowing the sky-diver to slow down and control their descent.

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