Answer to Question #127187 in Physics for masterji

Question

a 900kg roller coaster car starts from rest at point a(on hill) of a height,H,rolls down the track, goes around the ( points B(bottom loop) and C (top loop). Find the velocity at point C ,if the work done to move the roller coaster from point B to point C is 264870J.Given the dimensions are : H=80m, r =15m,
r(radius of loop)

Answer 1

$mgH=mgh+mv^2/2$

$mgh=W=246870J$

$v=\sqrt{2(mgH-mgh)/m}=\sqrt{2(900\cdot 9.81\cdot80-246870)/900}=31.95m/s$