A mass of 300 g is hung from a spring of unstretched length 12.0 cm. The mass causes the spring's length to become 16.0 cm.
Which of the following is the best estimate of the spring constant of the spring?
a. 0.8 Nm−1
b. 1.9 Nm−1
c. 7.5 Nm−1
d. 75 Nm−1