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? A s= 3/ 10m B s= 10/3m C m=3/10s D m=1/30s
I'm assuming that the length of the spring is s and the mass of the object is m. If that be the case, the direct variation equation, which a line btw, is
s = km where k is the constant of proportionality. We have to solve for k, the slope of the line, in order to determine the model for this situation.
9 = k(30) so
Now that we know, the slope of the line, we can rewrite the equation with the slope in place: