Newton's Laws/Conservation of Momentum/Kinetic Energy

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Homework Help Overview

The discussion revolves around a mid-term exam in Physical Science, focusing on concepts related to Newton's Laws, conservation of momentum, and kinetic energy. The original poster presents a series of questions regarding kinetic energy, potential energy, and momentum involving a bowling ball and a freight train.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants suggest the original poster look for relevant formulas for kinetic energy and momentum, and consider the conservation of energy principle for potential energy questions. There is a discussion on the appropriateness of providing help with homework questions.

Discussion Status

The discussion highlights a conflict regarding the rules of providing homework help, with some participants reiterating the guidelines against direct assistance with exam questions. There is a recognition of the original poster's desire to understand the material better, but a lack of consensus on how to proceed within the forum's rules.

Contextual Notes

Participants note the constraints of the forum's rules on homework help, emphasizing that direct solutions to exam questions are not permitted. The original poster expresses urgency due to an impending deadline for the exam.

lucidion24
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Hello, I have a mid-term for Physical Science due on Wednesday. It's a 5 question take-home mid-term. Now I know these questions may be trivial to some of you, but I am in college purely for a business degree and have no use for physics. I'm primarily just looking to pass this course. Now, don't think that I don't pay attention in class, because I do. I am a student with a 3.7GPA but I just cannot comprehend the way my instructor is teaching this class.. Anyway, here are the questions. Help with them are greatly appreciated.

1. A 2.5 kg bowling ball slides across the floor with a velocity of 4.0 m/s. The bowling ball has a kinetic energy and momentum of: _______ Joules and ________ kg*m/s

2. If you were to lift the same bowling ball to a height of 4 m above the floor, its potential energy would increase by _______ Joules

3. A freight train rolls along a track with a speed of 10 m/s. If it's speed were increased to 30 m/s, its kinetic energy would be increased by a factor of _______

4. A 100,000kg railroad car traveling at 5 m/s collides with a stationary railroad car of the same mass. If the two cars couple together after the collision, because momentum will be conserved, they will have a speed of ________ m/s

5. The acceleration of gravity at the surface of the Earth is 9.8 m/s^2. If the mass of the Earth could be doubled keeping its radius the same, the acceleration of gravity would then be _________ m/s^2

Homework Equations



If I knew, I probably wouldn't be asking..

The Attempt at a Solution



Once again, if I even knew were to begin, I might have an idea of what these solutions will be.

I am not here for an easy 100.. I would like to be able to understand what is taught. If someone could explain these questions to me in a means in which I would be able to understand, I would appreciate it very much. Time is limited, my exam is due 6PM Tomorrow CST. Thank you for your time, understanding, and help!
 
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I believe that it's against our rules to help you with this take-home test.
 
SammyS said:
I believe that it's against our rules to help you with this take-home test.

What is the point of homework help if it's against the rules to help with homework? That's a puzzling concept.. Oh well..
 
re 1.Try to find the formulae for kinetic energy and momentum.
re 2. Try using conservation of energy principle.
re 3. use formula of KE
re 4. use conservation of momentum.
 
lucidion24 said:
What is the point of homework help if it's against the rules to help with homework? That's a puzzling concept.. Oh well..

Re-read the Rules link at the top of the page. You agreed to those rules when you joined the PF. The Homework Help rules are quite clear.

This additional thread will help you understand why we have the HH rules that we do.

https://www.physicsforums.com/showthread.php?t=373889

This thread is locked. Do not post exam questions here in the future.

berkeman
PF Mentor
 
Last edited:

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