Kinematics 2d physics question help

In summary: Remember, practice makes perfect.In summary, the package of emergency rations is dropped from an Alaskan rescue plane at a height of 50 m above the ground. The package travels horizontally for a distance of 89.4 m before it impacts the ground. The package's y-component of velocity is 44.8 m/s, and the x-component of velocity is 89.4 m/s.
  • #1
yoyophysics1
7
0

Homework Statement


An Alaskan rescue plane drops a package of emergency rations to a stranded party of explorers. The plane is traveling horizontally at 100 m/s at a height of 50 m above the ground. What horizontal distance does the package travel before striking the ground? what is the veloicty of the package before it hits the ground?


Homework Equations


X=Vox(t)
Y=Yo+Voy(t)+1/2G(t)^2


The Attempt at a Solution


I found the x and y components but could not find time and further on. Any help is appreciated.
 
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  • #2
Let me ask you this:

when the package initial leaves the plane, what is it's y-component of velocity? Also, as the package travels towards the ground, does the x-component vary at all?

(side note: I am assume we are ignoring air resistance?)
 
  • #3
srmeier said:
Let me ask you this:

when the package initial leaves the plane, what is it's y-component of velocity? Also, as the package travels towards the ground, does the x-component vary at all?

(side note: I am assume we are ignoring air resistance?)

for the y component i got 44.8 and x component i got 89.4. I don't quite understand what you mean when you ask if the x component varies.

and yes, ignore air resistance. I am in my first year of physics so I am sure the problems can't be too complex for you guys.
 
  • #4
yoyophysics1 said:
for the y component i got 44.8 and x component i got 89.4. I don't quite understand what you mean when you ask if the x component varies.

How did you get those values? Are you sure the y component is 44.8 when the package leaves the plane?

Asking why the x component varies is the same as asking whether the package's horizontal speed changes. Does it?
 
  • #5
For the x component I used the equation: Vox=VoCOS(theta)

Um I would guess that the horizontal speed doesn't change because velocity is constant in the x direction?

sorry I am a complete newbie to physics and I am trying to study for a test that I am not completely ready for at the moment
 
  • #6
yoyophysics1 said:
For the x component I used the equation: Vox=VoCOS(theta)

Um I would guess that the horizontal speed doesn't change because velocity is constant in the x direction?

How did you get V0 or theta?

The package's horizontal speed is 100 m/s when it was dropped from the plane, so it follows that it must be 100 m/s throughout the package's flight.
 
  • #7
No, I don't know what you mean by the intial velocity vector. I've never heard of it before :/.

I think the package is traveling faster in the x direction because wouldn't it have an initial velocity of 100 m/s?
 
  • #8
I got theta by using tan^-1(50/100)

did i at least do that right?
 
  • #9
yoyophysics1 said:
I got theta by using tan^-1(50/100)

did i at least do that right?

well, think about that...

theta is in radians (or degrees), 50[m]/100[m/s] give you units of seconds.
 
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  • #10
Oh I see.

So I guess my question is how do I find the x and y components correctly because I obviously did them wrong the first time. When I find the x and y components then I can find theta using inverse tan, correct?
 
  • #11
I am going to state some of what is known, think about these quantities/ideas.

1) the x-component is constant because there isn't an acceleration in the x-direction.
2) the initial y-component is zero because that is how the problem is defined.
3) the package accelerates in the y-direction, this is due to gravity.

How can we use some of this?

(trigonometry isn't apart of this problem)
 
  • #12
Oh, I finally got it! those last three ideas really helped. i didn't realize that the initial y-component was supposed to be zero. Thanks a lot srmeier!
 
  • #13
yoyophysics1 said:
Oh, I finally got it! those last three ideas really helped. i didn't realize that the initial y-component was supposed to be zero. Thanks a lot srmeier!

My pleasure, I must sleep now ^^

as you continue your journey remember these things (and think about why I would tell you them):
1) the time in which it takes the object to travel form 50m to 0m in the y-direction is equal to the time in which the object travels horizontally in the x-direction.
2) to solve a quadratic equation google: the quadratic formula. (because the initial y-velocity is zero you don't need this formula but it may come up on your test)
3) to find a resultant vector given its components use the Pythagorean theorem.

If these hints confuse you at first that is ok. Take things one step at a time.
 
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What is Kinematics?

Kinematics is the branch of physics that studies the motion of objects without considering the forces that cause the motion.

What is 2D kinematics?

2D kinematics is the study of motion in two dimensions, taking into account both the horizontal and vertical components of an object's motion.

What are the basic equations of 2D kinematics?

The basic equations of 2D kinematics are displacement = initial velocity x time + 1/2 x acceleration x time^2, final velocity = initial velocity + acceleration x time, and average velocity = (initial velocity + final velocity) / 2.

How do I solve a 2D kinematics problem?

To solve a 2D kinematics problem, you need to identify the known and unknown values, choose the appropriate equations, and then solve for the unknown value using algebraic methods.

What are some common types of 2D kinematics problems?

Some common types of 2D kinematics problems include projectile motion, circular motion, and motion on an inclined plane.

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