Question 856876
Assuming no friction forces, the component of gravity does work equal to the kinetic energy of the car when it stalls. 
{{{F[g]*d=(1/2)mv^2}}}
{{{mgsin(30)*d=(1/2)mv^2}}}
{{{d=v^2/(2gsin(30))}}}
{{{d=(20)^2/(2(9.8)0.5)}}}
{{{d=40.82}}}{{{m}}}