ok... an 80 kg skier rides a 2700 m long lift to the top of a mountain. the lift makes 14.9 degree angle w/ horizontal what cvhange in skiers gravitational potential enery......
i tried to use w=mg(cos theta) (h0-hf) but i got wrong answer is this the wrong formula... maybe i am pluggin this in all wrong? please explain
2007-02-18 00:28:46 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The hypotenuse is 2700m Theta is 14.9 degrees and the hieght you wish to find is oposite 14.9 degrees so use
Height = sin(14.9)*2700 = 694.26m
Potential energy = height * mass * gravity
= 694.26*80*9.81 = 554.85 KJoules
2007-02-18 01:26:53 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Try using sin theta instead of cos.. because if you resolve g into components the value along the slope should be g x sin theta, taking upward vectors positive.
I get the answer as approximately 453.8 KJ using w = m x g x sin theta x h and g = 10 m/s2. Is that right? You might try refining your log calculations....
2007-02-18 08:59:49 · answer #2 · answered by beachblue99 4 · 1⤊ 0⤋
The formula used by you is the right formula, may be you are calculating it wrongly.
use g = 9.81 m / sq. sec
m = 80 Kg
h = 2700 m
@ = 14.9
2007-02-18 09:06:54 · answer #3 · answered by Thorian 1 · 0⤊ 0⤋