# Physics

posted by
**puff puff**
.

A curve of radius 60m is banked so that a car traveling with uniform speed 70km/hr can round the curve without relying on friction to keep it from slipping to its left or right. The acceleration of gravity is 9.8m/s^2. What the the Angle of the curve?

im using a=v^2/r, but when I get the acceleration, I don't know what to do no more.. Can anyone help me on this one? Thanks a bunch!

This is an "angle of lean" problem. You're right, first get the acceleration as you mentioned. You then have to set up your right triangle. The opposite side of the angle in question is the vertical component of force (the weight of the car), and the adjacent side of the triangle is the horizontal component of the force (in this case the mass x the centripetal acceleration...which you already calculated. Thus, the tangent of the angle of lean = opposite/adjacent

thus tangent angle = mg/ma, or just g/a.