Are you positive about part 2 in Helicopter Kinetics and Motion

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DarPodo
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Homework Statement



A helicopter is flying in a straight line over a level field at a constant speed of 6.8 m/s and at a constant altitude of 9.9 m. A package is ejected horizontally from the helicopter with an initial velocity of 11.0 m/s relative to the helicopter, and in a direction opposite the helicopter's motion.

1)Find the initial velocity of the package relative to the ground.

2)What is the horizontal distance between the helicopter and the package at the instant the package strikes the ground?

3)What angle does the velocity vector of the package make with the ground at the instant before impact, as seen from the ground?

Homework Equations



Vy2=Voy2-2*g*(y-yo)

Vy = Voy+g*t

The Attempt at a Solution



1) To find the initial velocity of the package to the ground I thought it was just a simple vector subtraction of 11m/s - 6.8m/s ... my online homework CAPA says that the result is not correct, but I don't know another method.

2) This problem requires me having the correct solution for part 1. I would use the time taken for the package to hit the ground (using t = v/g) and then do:
(t * the velocity from part 1) + (t*6.8) = distance traveled by the package when it hits the ground. I can't test that out unless I have part 1 correct.

3) Again, I would need part 1 correct, but I'm thinking it's just inverse tan to solve.
 
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DarPodo said:

Homework Statement



A helicopter is flying in a straight line over a level field at a constant speed of 6.8 m/s and at a constant altitude of 9.9 m. A package is ejected horizontally from the helicopter with an initial velocity of 11.0 m/s relative to the helicopter, and in a direction opposite the helicopter's motion.

1)Find the initial velocity of the package relative to the ground.

2)What is the horizontal distance between the helicopter and the package at the instant the package strikes the ground?

3)What angle does the velocity vector of the package make with the ground at the instant before impact, as seen from the ground?

Homework Equations



Vy2=Voy2-2*g*(y-yo)

Vy = Voy+g*t



The Attempt at a Solution



1) To find the initial velocity of the package to the ground I thought it was just a simple vector subtraction of 11m/s - 6.8m/s ... my online homework CAPA says that the result is not correct, but I don't know another method.

2) This problem requires me having the correct solution for part 1. I would use the time taken for the package to hit the ground (using t = v/g) and then do:
(t * the velocity from part 1) + (t*6.8) = distance traveled by the package when it hits the ground. I can't test that out unless I have part 1 correct.

3) Again, I would need part 1 correct, but I'm thinking it's just inverse tan to solve.

Maybe the answer you are getting for part 1 is not positive...
 
DarPodo said:
Maybe the answer you are getting for part 1 is not positive...
Talking to yourself, hey? :wink:I do it a lot myself. :smile: Yes, you are correct about part 1 not being positive, but are you positive:rolleyes: about your method in part 2? You have 2 relevant equations you did not list.