- #1

- 25

- 0

## Homework Statement

A 1200kg car rounds a dry curve (μ= .6)with a radius of 67 m banked at an angle of 12°. If the car is traveling @ 95 km/hr (26.4 m/s), will a friction force be required? If so how much and in what direction?

## Homework Equations

Fn = mg cos 12°

ƩFn sin 12° = m (v^2/r)

Ffrmax = μFn

## The Attempt at a Solution

Seen many different versions of this question asked so here is what I have attempted...

Vertical Force on the car at that angle

Fn = 1200 * 9.8 * cos 12°

= 1.2 x10^4 N

Horizontal force

ƩFn sin 12° = m (v^2/r)

ƩFn sin 12° = 1200 ( (26.4)^2/67)

= 5.8 x 10^4 N

max total static friction force of the

Ffrmax = μFn

= (.6) (1.2x10^4)

= 7200 N

Based on my answers I would say additional force would be needed (5.8 x 10^4 N-7200 N=5.1x10^4) perpendicular to the curve.

Would you guys agree or where have I gone wrong?