(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A new event has been proposed for the Winter Olympics. An athlete will sprint 100 m, starting from rest, then leap onto a 20 kg bobsled. The person and bobsled will then slide down a 50 m long ice covered ramp, sloped at 20°, and into a spring with a carefully calibrated spring constant of 2300 N/m. The athlete who compresses the spring the farthest wins the gold medal. Lisa, whose mass is 40 kg, has been training for this event. She can reach a maximum speed of 12 m/s in the 100 m dash.

How far will Lisa compress the string?

http://img258.imageshack.us/img258/5415/p1056ra6.gif [Broken]

2. Relevant equations

(0.5)*k*x_i^2 + (0.5)*m*v_i^2 + mgh = (0.5)*k*x_f^2 + (0.5)*m*v_f^2 + mgh

3. The attempt at a solution

0 + 0 + (40+20)(9.81)(50sin(20)) = 0.5*(2300)*(x_f)^2 + 0.5(60)(12)^2 + 0

after calculating everything, I'm getting

x_f = 2.23 meters

while the answer in the back is 3.2 meters. There's likely something in my solution that I missed. Could anyone point it out for me?

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# Homework Help: Spring/Energy Problem

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