X and Y components of a vector using a graph of speed/time

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The discussion focuses on determining the horizontal distance traveled and the maximum height attained by a golf ball based on its speed-time graph. The initial speed is identified as 29.3 m/s, with a minimum horizontal speed of 16 m/s, leading to the calculation of the angle theta at approximately 56.91 degrees. The horizontal distance is computed using the formula s = 0.5(v0 + v)t, resulting in a distance of 80 meters. For the maximum height, the vertical component of velocity is calculated to be 24.55 m/s, yielding a height of approximately 30.68 meters. The calculations and reasoning presented are confirmed as correct.
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Homework Statement



A golf ball is struck at ground level. The speed of the golf ball as a function of the time is shown in the figure, where t = 0 at the instant the ball is struck. The scaling on the vertical axis is set by va= 16 m/s and vb= 29.3 m/s. (a) How far does the golf ball travel horizontally before returning to ground level? (b) What is the maximum height above ground level attained by the ball?
[PLAIN]https://edugen.wileyplus.com/edugen/courses/crs7165/art/qb/qu/c04/fig04_40.gif[/B]

Homework Equations


x component=|magnitude of vector|cos(theta)
y component=|magnitude of vector|sin)theta)
s=.5(v0+v)t

The Attempt at a Solution


16 m/s is the minimum value on this graph and 29.3 is the maximum value on this graph. 29.3 appears first and then 16 is in the middle in a concave-up parabola. So this is what I did and I wonder if this is right:
So the initial velocity, a mixture of both x and y components is=29.3. To find the theta, we can take 29.3cos(theta)=16. Why do we use 16? Because the minimum speed corresponds to a vertical velocity of 0, meaning 16 is the constant horizontal velocity. So then, theta is =56.91 degrees. We then have to solve for initial y component of velocity, so we have 29.3sin(56.91)=24.55. We then say, since the graph has 5 seconds at the end point: s=.5(16+16)*5=80m. Is that right? for a. And then is b just s=.5(24.546+0)*2.5=30.6825? Thanks for the help, I just am unsure. Thanks and have great day :)
 
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The image of the graph is attached below:
 

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  • fig04_40.gif
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Looks right to me.
 
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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