Mollie is using springs to hang art projects. (I'm
using springs to hang art projects. (I'm not sure why. Ask her.) She hangs a 3.0 kg picture
on one particular spring and it stretches from 30 cm to 45 cm long.
a) What is the spring constant for that spring?
b) If she hangs a 2 kg picture beneath the first one, how long will the spring get?

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.