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.

Potential energy    is energy an object has because of its position relative to some other object. when you stand at the top of a stairwell you have more potential energy than when you are at the bottom, because the earth can pull you down through the force of gravity, doing work in the process. when you are holding two magnets apart they have more potential energy than when they are close together. if you let them go, they will move toward each other, doing work in the process.the formula for potential energy depends on the force acting on the two objects. for the gravitational force the formula is  p.e. = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s2  at the surface of the earth) and h is the height in meters. notice that gravitational potential energy has the same units as kinetic energy, kg m2  / s2. in fact,  all  energy has the same units, kg m2  / s2, and is measured using the unit joule (j).pe=mx(9.8 m/s^2)x(0.45m)