# physics bob

posted by
**anthony**
.

still i cant find the normal force without mass of automabile. is normal force mass times gravity sin theta?

on a level road the stopping distance for an automobile is 35.0m for an initail speed of 90 km/hr what is the stopping distance of the same automobile on a simalr road with the slope 1:10

physics - bobpursley, Saturday, October 30, 2010 at 7:42am

Assume the coefficent of friction is the same.

F=mu*Normal force=ma

a= normalforce*mu/mass

Vf^2=Vi^2+2ad

solve for mu on the level road, knowing normalforce is mg.

Then, knowingmu, look at the slope

normal force=mg*SinTheta

Vf^2=Vi^2+2mgSinTheta*mu/m * d

solve for distance.

since Theta is a small angle, SinTheta=TanTheta= 1/10