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Seraph404
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Homework Statement
For sport, a 12 kg armadillo runs onto a large pond of level, frictionless ice with an initial velocity of 5.0 m/s along the positive direction of an x-axis. Take its initial position on the ice as being the origin. It slips over the ice while being pushed by a wind with a force of 17N in the positive direction of the y-axis. In unit-vector notation, what are the animal's (a) velocity and (b) position vector when it has slid for 3.0 seconds?
Homework Equations
Fnet=ma
Kinematic Equations
Other equations depend on the free body diagram(s).
The Attempt at a Solution
I feel like I'm on the verge of getting this one; I just need a hint. ><
If the ice is frictionless, that means the armadillo is still sliding at a constant velocty of 5.0 m/s after he slips, right?
I think it's finding the upward velocity on part (a) that I'm kind of having trouble with.
What I did first was draw a free body diagram for the armadillo at the second position where two forces (I think) are working on the animal: The force of the wind (17N) upward, and mg downward. Was that correct, or am I missing one? I used a = (w - mg)/m (from w-mg = ma), where w is equal to the force of the wind, to find the acceleration, which came out as -8.38 m/s^2, for me. I really don't know if that's right or not. Then I tried to use the kinematic equation v = v0 + at to find the upward velocity. I rearranged the equation to v - at = v0; I remember from free-fall motion that when an object reaches its max upward height, v=0; also, I used the acceleration -8.38 m/s^2. My answer came out to be 4.26 m/s for the upward velocity, which is close to the right answer (to correct sig figs, the answer should be 4.2 m/s in the positive y direction). I still feel like I missed something. Can somebody show me where I might have gone wrong?
[Edit] Nevermind; I don't think this works after all. D:
Also, for part (b), can I just use kinematics to find x and y after 3.0 seconds? (I don't want to try it yet until I know I have part (a) right)
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