The length of a spring varies directly with the mass of an object that is attached to it. When a 30-gram object is attached, the spring stretches 9 centimeters. Which equation relates the mass of the object, m, and the length of the spring, s?
s = StartFraction 3 Over 10 EndFraction m
s = StartFraction 10 Over 3 EndFraction m
m = StartFraction 3 Over 10 EndFraction s
m = StartFraction 1 Over 30 EndFraction s