1. A force of 720 N stretches a certain spring a distance of 15 cm. What is its force constant? If a 60-kg mass is hang on it, how far will it stretch?

Answer 1

k = 720N/15cm = 48N/cm

F = m*g = 60kg * 9.8N/kg = 588 N.
d = 588N/48N * 1cm = 12.25 cm.