Off Topic A place for you CBR junkies to boldly go off topic. Almost anything goes.

Physics Help

Thread Tools
 
Search this Thread
 
  #1  
Old 04-25-2008, 05:26 PM
MikeZ's Avatar
Senior Member
Thread Starter
Join Date: Jan 2008
Location: Granger, Indiana (Next to South Bend and Notre Dame)
Posts: 287
Likes: 0
Received 0 Likes on 0 Posts
Default Physics Help

Ok...so I'm doing a physics problem for homewrk and a part of this question I can't figure out.

A professional skier reaches a speed of 37 m/s on a 24 degree ski slope. Ignoring friction, what was the minimum distance along the slope the skier would have had to travel, starting from rest?

How do I get acceleration with gravity and the 24 degree slope?
 
  #2  
Old 04-25-2008, 06:55 PM
Join Date: Apr 2007
Location: Chicago
Posts: 172
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

Instead of a skier going down a slope, turn the problem into a box down a ramp at 24 degrees. The box has one force acting on it, gravity straight down. Change your coordinate system for ths problem. The X-axis should be parallel to the ramp and the Y-axis should be perpendicular to the ramp. The force of gravity will be between the new X and Y axis. Split this force up into two components, one along the X and one along the Y. Do the trig to solve for the acceleration in the X direction. I think the answer is ax = 9.8*sin(24) but its been a year since I've been in Physics.



Name:  phys.jpg
Views: 8
Size:  36.5 KB
 
  #3  
Old 04-25-2008, 06:57 PM
DFour's Avatar
Senior Member
Join Date: Jun 2007
Location:
Posts: 517
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

whats the skiiers mass?
 
  #4  
Old 04-25-2008, 07:01 PM
Join Date: Apr 2007
Location: Chicago
Posts: 172
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

ORIGINAL: DFour

whats the skiiers mass?
F = m*a

If you only need the acceleration, the mass does not matter. Every body feels the same acceleration regardless of its mass.
 
  #5  
Old 04-25-2008, 07:52 PM
MikeZ's Avatar
Senior Member
Thread Starter
Join Date: Jan 2008
Location: Granger, Indiana (Next to South Bend and Notre Dame)
Posts: 287
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

Thanks for the help, btw....you got nice hand writing
 
  #6  
Old 04-25-2008, 08:06 PM
Join Date: Apr 2007
Location: Chicago
Posts: 172
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

ORIGINAL: MikeZ

Thanks for the help, btw....you got nice hand writing
Alot of people say that , but I don't think its true. No problem. Is the answer correct?
 
  #7  
Old 04-25-2008, 08:08 PM
rangerscott's Avatar
Senior Member
Join Date: Jun 2007
Location: Texas
Posts: 4,412
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

ORIGINAL: MikeZ

Thanks for the help, btw....you got nice hand writing

Lets keep on subject tiger.
 
  #8  
Old 04-25-2008, 08:19 PM
Nauree's Avatar
Senior Member
Join Date: Jun 2007
Posts: 3,099
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

U = K

mgy = 1/2mv^2

y = 1/2(37^2)/(9.8)

The angle of the slope doesnt matter with the conservation of energy formula.


 
  #9  
Old 04-25-2008, 08:29 PM
Join Date: Apr 2007
Location: Chicago
Posts: 172
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Physics Help

There are often many ways to solve a problem. I didn't think of using the conservation of energy. You will need to do mgh1 = mgh2 + .5mv^2. You will have to solve for h2 than use trig to find the distance. Probably the easier/faster way to solve the problem, but thats the first solution I came up with.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
regener8ed
Riding Skills
5
11-24-2015 02:45 AM
rocketsauce035
Off Topic
5
11-20-2009 01:10 AM
woo545
Off Topic
5
12-19-2008 05:47 PM
specializedfuji
Off Topic
28
04-04-2008 03:04 PM



Quick Reply: Physics Help



All times are GMT -5. The time now is 09:03 PM.