Finding the acceleration of a car based on a velocity vs time plot

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To find the acceleration of a car from a velocity vs. time plot, the average acceleration can be calculated using the formula Δv/Δt. The discussion emphasizes that while the overall average acceleration can be determined from the slope between the first and last points, specific gear accelerations require focusing on the initial and final points within each gear's range. For example, to calculate the average acceleration in second gear, one should identify the start and end points of that gear and compute the slope between them. This method ensures accurate results for each gear's performance. Understanding how to interpret the graph correctly is crucial for obtaining the right values.
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Homework Statement


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Homework Equations


Unsure, maybe v2-v1/t2-t1?

The Attempt at a Solution


I assumed taking the difference between the final point in the graph and the first one and got 1.53m/s2 as an answer, but I'm not sure at all. Should i take the differences between all the gears and then average them?
 
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Remember that acceleration is the slope on a velocity/time graph. You've got the right equation, average acceleration is Δv/Δt. If you found the slope between the first point and the final point, you'd find the average acceleration across all 5 gears. However, the question asks for the average acceleration in specific gears.

For part a, for example, which asks for the average acceleration in second gear, you'll want to make your initial point at the start of 2nd gear (at the first flat spot) and your final point at the end of 2nd gear (the 2nd flat spot). The slope between those two points will give the average acceleration in gear 2.
 
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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