Working With 1D Constant Acceleration Kinematics

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The discussion centers on a first-year physics student's confusion regarding a homework problem involving 1D constant acceleration kinematics. The student understands the basic concepts of velocity and displacement but struggles with demonstrating the average velocity formula and eliminating time from the equations. Key points include the need for two equations involving time to eliminate it effectively and the importance of understanding the geometric representation of the area under the velocity-time graph. The conversation highlights the necessity of integrating the definitions of acceleration and average velocity to solve the problem. Overall, the student seeks clarity on these concepts to complete the assignment successfully.
Entangled Cat
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Hello, this is my first post on PhysicsForums. I'm a first year student at the University of Kansas pursuing a Bachelor of Science in Physics and Astronomy (double majoring). The wording on my homework (for Honors General Physics 1) is a little bit strange to me so maybe some of you guys and girls can help me iron it out. Thanks in advance!

1. Homework Statement

Draw a graph of velocity versus time of an object starting with a velocity v0 and increasing speed with a constant acceleration(this is easy and not a problem). We know that v-v0=∫vdt (this is also quite obvious and easy to deduct), so the displacement is the area under the plot you just drew(simple integration). Show that for this case (constant acceleration): vave=1/2(v0+v) - (although I know this is true, I don't exactly know how to "show" it?), and then, by equating this result with the definition of vave and eliminating t(this is ultimately what hangs me up. I have no idea how to eliminate t. I know that the definition of vave) = Δx/Δt but I am not sure how to rid the equation of time), v2=v02+2aΔx

Homework Equations


v2=v02+2aΔx
vave) = Δx/Δt
ave=1/2(v0+v)

The Attempt at a Solution


Since this is more of a conceptual approach to understanding this idea, I have very little work done for this specific problem. I have finished the other two problems in the question set though (total of 3 problems).
 
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Entangled Cat said:
v-v0=∫vdt
s-s0?
Entangled Cat said:
vave=1/2(v0+v)
This is just geometry. What shape have you drawn? How would you find its area?
Entangled Cat said:
and eliminating t
There seems to be something missing here in the instructions. To eliminate t you need two equations involving t. The other equation you need is the definition of acceleration.
 
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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