My Math Forum  

Go Back   My Math Forum > Science Forums > Physics

Physics Physics Forum


Reply
 
LinkBack Thread Tools Display Modes
December 23rd, 2010, 02:11 PM   #1
Senior Member
 
Joined: Oct 2009

Posts: 895
Thanks: 1

why we use this formula

A 50-kg pole vaulter running at 10 m/s vaults over the bar. Her speed when she is above the bar is 1.0 m/s...?
Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar.

In my book the soving start by (1/2)mvi = (1/2)mvf + mgh

please help me ..
r-soy is offline  
 
December 23rd, 2010, 02:24 PM   #2
Senior Member
 
MarkFL's Avatar
 
Joined: Jul 2010
From: St. Augustine, FL., U.S.A.'s oldest city

Posts: 12,211
Thanks: 520

Math Focus: Calculus/ODEs
Re: why we use this formula

Your book is equating total initial energy to total final energy.







and thus:

MarkFL is offline  
December 23rd, 2010, 09:42 PM   #3
Senior Member
 
Joined: Oct 2009

Posts: 895
Thanks: 1

Re: why we use this formula

But we use here (total initial energy to total final energy) tell my the concept about this Q
r-soy is offline  
December 23rd, 2010, 09:54 PM   #4
Senior Member
 
MarkFL's Avatar
 
Joined: Jul 2010
From: St. Augustine, FL., U.S.A.'s oldest city

Posts: 12,211
Thanks: 520

Math Focus: Calculus/ODEs
Re: why we use this formula

Well, as I said before, we are setting the total initial energy equal to the total final energy. Just as the vaulter leaves the ground, all of her energy is kinetic, or relating to motion, then during the vaulting process, some of her kinetic energy is converted into gravitational potential energy. While she now has two forms of energy, the sum total remains constant. As the kinetic energy is converted into potential energy, she slows down.

In the problem, her negative change in kinetic energy is countered by a positive increase in potential energy. It is through the fact that her total energy remains constant that we can find her altitude, knowing her initial and final velocities.

This is the same fact that we use in a variety of problems involving changes in kinetic and potential energies.
MarkFL is offline  
Reply

  My Math Forum > Science Forums > Physics

Tags
formula



Search tags for this page
a 50 kg pole vaulter running at 10m/s
,

a 50 kg pole vaulter running at 10m/s vaults over the bar. her speed when she is over the bar is 1.0 m/s. neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar

,

a 48-kg pole vaulter running at 10m/s vaults over the bar. her speed when she is above the bar is 1.0 m/s. neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar.

,

a 50 kg pole vaulter running at 10 m/s

,

A 50-kg pole vaulter running at 10m/s vaults over the bar. Her speed when she is above the bar is 1.0 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar

,

a 50 kg pole vaulter running at 10m/s vaults over the bar

,

"a 50kg pol

,

a 50 kg pole vaulter running at 10m/s vaults over the bar. her speed when above the bar is 1.0m/s. neglect air resistance as

,

A 50-kg pole vaulter running at 10 m/s vaults over the bar. Her speed when she is above the bar is 1.0 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar

,

a 50 kg pole vaulter

,

a 50-kg pole vaulter running at 10m/s vaults over the bar. her speed when she is the bar is 1.0m/s

,

a 50 kg pole pole vaulter running at 10m/s

,

a 50-kg pole vaulter running at 10m/s vaults over the bar. her speed when she is above the bar is 1.0 m/s neglect air resistance, as wells as any energy abosrbed by the pole, and determine her altitude as she crosses the bar

,

a 48 kg pole vaulter running at 10m/s

,

A 54.6 kg pole vaulter running at 11.9 m/s vaults over the bar. Her speed when she is over the bar is 1.38 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar. 

Click on a term to search for related topics.
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Formula Help NuNu_dagobah Computer Science 4 January 8th, 2013 08:31 AM
My new formula for pi(x) nsrmsm Number Theory 7 October 15th, 2012 06:36 AM
Formula to always get 28 djx18 Algebra 1 September 20th, 2009 06:25 PM
De Moivre's formula and Newton's binomial formula agro Probability and Statistics 3 August 27th, 2009 07:17 AM
Formula Help NuNu_dagobah Abstract Algebra 0 December 31st, 1969 04:00 PM





Copyright © 2019 My Math Forum. All rights reserved.