A bar magnet of mass 250 g is suspended from the free end of a spring and oscillates vertically; one pole is near the centre of a coil connected in series with a resistor and a switch. At t = 0 the magnet oscillates freely; at t = 6.0 s the switch is closed.

For the oscillating magnet, use data from Fig. 3.2 to determine, to two significant figures, the energy of the oscillations during the time interval t = 0 to t = 6.0 s.