Solving Distance w/ Initial Velocity: Lab Homework

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Homework Help Overview

The discussion revolves around a lab experiment involving a chalkboard eraser projected by a slingshot. Participants are tasked with calculating the distance the eraser travels, given only the initial velocity of 13 m/s, without direct observation of the distance traveled.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants express uncertainty about calculating distance with limited information, questioning the necessity of additional parameters such as time or friction. Some suggest using kinematic equations while others explore the implications of the launch angle.

Discussion Status

There is an ongoing exploration of possible methods to approach the problem, with participants offering various suggestions and considerations regarding the role of friction and the need for time measurements. No consensus has been reached on a definitive method or formula.

Contextual Notes

Participants note constraints such as the lack of observed distance and time during the experiment, as well as the requirement to derive a formula based solely on the initial velocity provided by the instructor.

microdoodle
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Homework Statement


We are doing a lab where the teacher took an chalkboard eraser and he put it between to rulers in a hallway. He used some sort of slingshot to project that eraser.( we did not see how far the eraser went) We have to find how far the eraser will travel in meters. All we were given was an initial velocity of 13. We have to find the distance using that number.


Homework Equations





The Attempt at a Solution


I know velocity is m/s but all we know is the initial velocity. I don't think its possible to find the distance with this much information. Please help. (We are learning derivative and integrals that might help I'm not quite sure)
 
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microdoodle said:

Homework Statement


We are doing a lab where the teacher took an chalkboard eraser and he put it between to rulers in a hallway. He used some sort of slingshot to project that eraser.( we did not see how far the eraser went) We have to find how far the eraser will travel in meters. All we were given was an initial velocity of 13. We have to find the distance using that number.

Homework Equations



The Attempt at a Solution


I know velocity is m/s but all we know is the initial velocity. I don't think its possible to find the distance with this much information. Please help. (We are learning derivative and integrals that might help I'm not quite sure)

If the angle was horizontal, then you can figure it out. The horizontal velocity times the time to drop from rest will tell you how far it went.
 
LowlyPion said:
If the angle was horizontal, then you can figure it out. The horizontal velocity times the time to drop from rest will tell you how far it went.

The instructor is shooting the eraser on the floor in the hallway. So the angle is 180 degrees right? but he shoots the eraser forward horizontally he does not drop it. Also we don't know how long the eraser travels on the floor. Is their a formula to solve this problem with just the initial velocity
 
microdoodle said:
The instructor is shooting the eraser on the floor in the hallway. So the angle is 180 degrees right? but he shoots the eraser forward horizontally he does not drop it. Also we don't know how long the eraser travels on the floor. Is their a formula to solve this problem with just the initial velocity

Oh. I see not through the air. Well then you need to know what the coefficient of friction is with the floor. That is the retarding force.

So distance is given by Vf2 = Vo2 + 2*a*x

But a is unknown.

Determine a is what you need for that

Otherwise time it until it stops. Then you can figure the distance. Or the a and just use the velocity formula.
 
LowlyPion said:
Oh. I see not through the air. Well then you need to know what the coefficient of friction is with the floor. That is the retarding force.

So distance is given by Vf2 = Vo2 + 2*a*x

But a is unknown.

Determine a is what you need for that

Otherwise time it until it stops. Then you can figure the distance. Or the a and just use the velocity formula.

I am really sorry for not being clear enough and wasting your time. The teacher did the lab outside so we could not see how long it took the eraser to move or how far the eraser went. When he came inside he said the initial velocity is 13 and he told us to find a formula and predict how far the eraser went. We do not know seconds and we have to solve for meters but my guess is it traveled around 14 meters? ( I have no clue on how to solve it with a formula that i have to create on the second week of first year physics with only one number initial velocity of 13)
 
microdoodle said:
I am really sorry for not being clear enough and wasting your time. The teacher did the lab outside so we could not see how long it took the eraser to move or how far the eraser went. When he came inside he said the initial velocity is 13 and he told us to find a formula and predict how far the eraser went. We do not know seconds and we have to solve for meters but my guess is it traveled around 14 meters? ( I have no clue on how to solve it with a formula that i have to create on the second week of first year physics with only one number initial velocity of 13)

Get an eraser (the same eraser?) and slide it along the floor. Time it until it stops. Measure the distance.

Then apply what you find to the initial condition he gave you.
 
LowlyPion said:
Get an eraser (the same eraser?) and slide it along the floor. Time it until it stops. Measure the distance.

Then apply what you find to the initial condition he gave you.

One last question. He used a sling shot so i assume the eraser is f;lying down the hallway. I did not see how fast it was going so how do i know how fast i should slide it along the floor.
 
microdoodle said:
One last question. He used a sling shot so i assume the eraser is f;lying down the hallway. I did not see how fast it was going so how do i know how fast i should slide it along the floor.

Doesn't matter. x = 1/2 a t2

Time and distance yields a.

Then you can use the first equation where he told you it was 13m/s

132 = 02 + 2*a*x

The best he could have done is launch it at a 45 degree angle. And you can calculate that distance.
 
Last edited:
LowlyPion said:
Doesn't matter. x = 1/2 a t2

Time and distance yields a.

Then you can use the first equation where he told you it was 13m/s

132 = 02 + 2*a*x

The best he could have done is launch it at a 45 degree angle. And you can calculate that distance.

Thank You
 

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