# Homework Help: Banked road need to find the angle

1. Dec 18, 2007

### LDRshipphysic

Calculate the angle at which a road should be banked for a design speed of 43 km/h and a radius of .0075 km.

Givens : radius: .075km = 75m
Vt(maybe?): 43 km/h = 11.944m/s

Unknown: angle

Im not shure about what equations to go about solving this for i know in the end im probly going to have to cancil out mass's because that isn't given to you.. If anyone can help me it would be soooo nice!

:yuck:

2. Dec 18, 2007

### LDRshipphysic

What i attempted to do so far was

Fc=(mvt^2)/r i think i know what the diargram should look like, im unshure on how to solve for the componits that make up the diargram tho such as Fnx, and Fny, if there was some way i could figure out the compents for Fn then i could figure out how to solve for the angle using trig functions

3. Dec 18, 2007

### LDRshipphysic

But because i dont know the mass of the object im unshure how to go about solving it

4. Dec 18, 2007

### LDRshipphysic

How do u get

Ok, in my physics homework i know the equation that i have to use is tan(θ) = v2/rg but i dont know how you get to that, if there is some way to find out, that would be sweet for your assistance. I know that v2/r is equail to the centripital acceleration but ya im not shure the base equations that would be used, If you can help that would be great thanks.