hanging, accelerated spring-mass system. For the three-mass configuration in an elevator at rest, what is the force Fspring,top that the top spring exerts on the top mass? Macmillan Learning In the first configuration, a single mass m1 = 3.30 kg hangs from a massless spring in a motionless elevator. The spring extends a length y = 13.0 cm from its unstretched length. 64.7 Fspring,top N (Scroll down for the second configuration.) Incorrect Ly m 1