Archived Did I make the velocity vs time graph correctly?

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The discussion focuses on creating a velocity vs time graph based on the slopes of a distance-time graph. The user successfully calculates slopes for each segment, identifying various motion types, but questions the correctness of their velocity graph, which consists of horizontal segments. It is confirmed that the velocity graph's segments reflect the slopes from the distance-time graph. The conversation clarifies that sudden changes in velocity result in large accelerations, leading to instantaneous spikes in the acceleration-time graph, rather than just horizontal lines. Overall, the user is guided on accurately interpreting the relationship between velocity and acceleration in their graphs.
ziltoid
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Homework Statement


a) Calculate the slope for each segment
b) Describe the motion the object experiences in each segment
c) Make a velocity vs time graph using the slopes
d) Make a acceleration time graph

(for the distance-time graph)
Segment A slope of zero
Segment B constant slope of +1
Segment C slope of zero
Segment D sharp change to slope of -3
Segment E sudden change to slope of zero
Segment F constant slope of -2/5
Segment G slope of zero


Homework Equations



slope = deltaY/deltaX
acceleration = deltaV/deltaT



The Attempt at a Solution



I'm fine on a and b, but for c my graph just has horizontal segments at varying y values that correspond to the earlier velocities (slopes). I think this may be wrong. Anyway if it isn't does that mean that my acceleration-time graph will be a load of horizontal lines since all the velocity changes were sudden and constant?
 
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ziltoid said:

I'm fine on a and b, but for c my graph just has horizontal segments at varying y values that correspond to the earlier velocities (slopes).


That is correct. The Velocity in each section is the slope of the distance/time graph in that section.

...does that mean that my acceleration-time graph will be a load of horizontal lines since all the velocity changes were sudden and constant?

No. The acceleration at any instant is equal to the slope of the velocity/time graph at that instant. Sudden or rapid change in velocity mean large acceleration. The Velocity graph has instantaneous changes in velocity followed by periods of constant velocity. This means infinite acceleration for very short periods of time followed by periods of zero acceleration.
 
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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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