A curve of radius 59.9 m is banked so that a car of mass 1.4 Mg traveling with uniform speed 50 km/hr can round the curve without relying on friction to keep it from slipping on the surface.

Question

At what angle is the curve banked? The acceleration due to gravity is 9.8 m/s2

* I swear I am doing this correctly I had it all set up and I keep getting 18.85 degrees but it says its wrong

Answer 1

50/km/h=13.9 m/s
m•a=N•sinα
0=N•cosα - m•g
m•v²/R=N•sinα = m•g•sin α/cos α =m•g•tan α

tan α = v²/gR =13.9²/9.8•59.9=0.329
α = tan⁻¹=18.19⁰