The bob (weight) at the end of a pendulum has a mass of 0.3 kilograms. the bob is pulled to position b and allowed to swing. it goes all the way to position c and swings back. the potential energy of the bob at position b is joules. if the maximum height of the bob is 0.45 meters when it swings back, joules of energy was transformed to thermal energy. use g = 9.8 m/s2 and pe = m × g × h.