physics hey bob
posted by anthony on .
you help me solve this problem. but how am i suppose to if i don't know the mass of the car?
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

YOu are supposed to realize that you have m/m and it divides out.
normalforce*mu/mass= mgSinTheta*mu/m