Calculating Velocity Without Time Factor | Physics Homework

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Homework Help Overview

The discussion revolves around calculating velocity in a physics problem where the time factor is not directly available. The original poster is attempting to create a problem for classmates involving concepts such as drag, terminal velocity, and various physical properties of an object in free fall.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between velocity, distance, and time, questioning whether time can be treated as a variable. Some suggest that the original poster might need to clarify the problem further. Others inquire about the presence of acceleration and how it relates to the calculations.

Discussion Status

The conversation is ongoing, with participants providing insights on how to approach the problem. There is a focus on understanding the implications of the given parameters and how they relate to calculating velocity and drag. Multiple interpretations of the problem setup are being explored.

Contextual Notes

Participants note that the original poster is working with a set of known variables, including drag coefficient, mass, and distance, but lacks the time and velocity components. There is an emphasis on the challenge of creating a problem with many unknowns while adhering to the constraints of the assignment.

Sesquipedalian
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I am just getting into physics and I have met a problem, I have almost all of the information I need to make a problem for other students in my class but the problem is I do not have the time factor in v=d/t is there any other way that I am able to calculate for Velocity?
 
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dx/dt

Velocity is the time derivative of the inital position function x(t). You need time. Perhaps your time value is meant to be a variable. It would help if you descrbed your problem a little more



EDIT:
If you are given the directional velocities(D.V.) i.e velocities in the x, y, and z directions, you can find the overall velocity by adding the squares of the D.V. and taking the squareroot
 
Last edited:
Do you have accelleration?
 
I don't think I was fully clear, I am trying to make a problem for fellow students in my class (I'm in 7th Grade). For my problem I don't have an acceleration because I am trying to make up the whole thing from (almost) scratch. What I have is the Drag Coefficient, Distance, Mass, Density, Volume, and Area. What I am trying to do is calculate the time it would take to fall an x amount of distance then make it into a problem using everything. And in the end it will ask them to calculate for Drag and Terminal Velocity. The problem really won't be very complicated, but the only thing I still need is velocity, so I can solve for q in Drag=mg-qv^2.

I guess what I should be asking is if there is a different way to find time besides t=d/v because if I had the velocity wouldn't I know the time in the first place? Or maybe is there a different way to find Drag and q without knowing Velocity?

EDIT: Problem will be somewhat like a problem with a lot of unknowns but they can be found easily..

A 20x10x5 brick with a volume of a, a density of b, and a mass of 2.27kg is falling from a height of c, the time it takes for it to fall that distance is (?) when the velocity=(?), the Drag Coefficient of this brick is 2.1. With that information solve for each of the unknowns and then solve for Drag and Terminal Velocity whereas Drag=mg-qv^2 and where q=1/2ρCdA. Vt(Terminal Velocity)=squareroot(2mg/CdρA).

The (?)'s are the things I don't know yet.
 
Last edited:
Is it falling from rest? If so, they can use

x=v-initial *t +1/2*a*t^2

And if it's falling, you do have an acceleration, g.
 
You mean the acceleration due to gravity, 938m/s^2?

And its just being dropped, to find the velocity will I have to a website that has done this with a falling brick and calculated its velocity by experiments, or is there a different way I could be able to find what t is equal to?
 

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