Johanna carries out an investigation where she uses a motor to lift different masses. She calculates the amount of energy transferred to a gravitational
potential energy store when the mass moves up and uses an energy meter to
measure the amount of energy transferred electrically by the motor.
а In one trial she calculates that the energy in the gravitational potential
store is 1.2 J. When she uses the motor to lift the mass she finds that the
energy meter gives a reading of 2.3).