Finding Distance from the Origin Given Velocity Graph

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The discussion revolves around calculating the distance of a rocket-powered hockey puck from the origin after 4 seconds, using its velocity graphs. The user initially calculated the areas under the velocity graphs to find the x and y components of distance, resulting in a total distance of 136 cm. However, the answer was marked incorrect due to formatting issues related to significant figures. After clarification, the correct answer was determined to be 1.4 meters when rounded to two significant figures. The user successfully resolved the issue after understanding the requirement for significant figures.
pocketofcandy
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Homework Statement


A rocket-powered hockey puck move along a horizontal friction-less table. The figure (link posted below) shows the graphs of vx and vy, the x- and y- components of the puck's velocity. The puck starts at the origin. How far from the origin is the puck at 4 seconds?

Here is the picture of the two graphs: https://session.masteringphysics.com/problemAsset/1384028/7/4-9.jpg

[moderator's edit: Here's an inserted copy of the image just in case the link evaporates some day]
upload_2016-9-18_14-15-13.png

Homework Equations


area of a triangle: 1/2(b)(h)
area of a square: (l)(w)
sqrt(x2+y2)

The Attempt at a Solution


It appears on the on the vx graph that the velocity increases by an increment of 8 cm every second. (It is confirmed to be at 40 cm at 5 seconds). So I thought the way to do this would be to find the area under both graphs from 0 to 4 seconds.
On the vx graph, I found the area to be 1/2*4*32 = 64 cm. On the vy graph, I found the area to be 30*4 = 120 cm. Then I tried to use the formula for distance to solve and came out with:
sqrt(642 + 1202) = 136 cm.

However, whenever I put this answer in, it says it is incorrect. I guess I'm not really the best at physics, so I'm wondering where it was I made the error? I appreciate any help.
 
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Strange as your answer seems to be correct at least from my judgement
I suppose make sure your answer is rounded correctly and that if required your answer is inputted with the correct units
Other than that I do not see an issue with your method
Maybe significant figures or something?
 
Oh I see now that the site wants the answer to two significant figures. So that would be 1.4 meters then?
 
pocketofcandy said:
Oh I see now that the site wants the answer to two significant figures. So that would be 1.4 meters then?
I believe so
 
It worked that time. Thank you!
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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