Constant Acceleration in a Runner's Straight Line Progression?

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SUMMARY

A runner who covers half the remaining distance to the finish line every ten seconds does not maintain a constant acceleration. Instead, her speed decreases over time as the distance to the finish line diminishes. Initially, she travels a significant distance, but as she approaches the finish line, the distance covered in each subsequent interval becomes smaller, indicating a change in speed. Therefore, her acceleration is not constant but rather decreases as she nears the finish line.

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a runner runs half the remaining distance to the finish line every ten seconds. she runs in a straight line and doesn't ever reverse her direction. does her acceleration have a constant magnitude? give a reason for your answer


i want just to know the situation
 
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Consider the parameters given. Take time intervals of ten seconds. Consider the distance traveled in the first ten seconds, the distance traveled in the next ten seconds, and so on. Then consider how her speed changes. That's your answer.
 
thanks a lot
 
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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