How to calculate the height of a skier

  • Thread starter Thread starter JiJiasd
  • Start date Start date
  • Tags Tags
    Height
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
6 replies · 2K views
JiJiasd
Messages
7
Reaction score
0

Homework Statement


I want to calculate the height h of the skier in this figure
upload_2016-5-23_16-6-52.png


Homework Equations


potential energy and kinetic energy and there is no friction

The Attempt at a Solution



mgh = 0,5 *m*v^2
v=√ (2*g*h)

Now calculate the h when he goes up

mgh= 0,5 *m*√ (2*g*h)^2Am I doing right ?

Thanks
[/B]
 
Physics news on Phys.org
JiJiasd said:
Now calculate the h when he goes up

mgh= 0,5 *m*√ (2*g*h)^2
What you got is an identity. You need more information of the person on the top of the hill to get his condition, such as velocity~
 
mgh = 0,5 *m*v^2
v=√ (2*g*h)

This is right but after this, only calculate with its vertical component (v*sin(28 deg)), when calculating h.
 
tommyxu3 said:
What you got is an identity. You need more information of the person on the top of the hill to get his condition, such as velocity~
These informations are enough, you don't need more!
 
You only got an identity, because you didnt calculate with the right component of speed.
 
You need to be careful with 'h'. There is a specific height in the problem which is labelled h, and there is the generic h in the equation gh=v2/2. Don't get them mixed up.
First, find the velocity at the launch point.