Question

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.

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