A block of mass 0.40 kg slides in a straight line with a constant speed of 0.30 m s⁻¹ along a horizontal surface, as shown in Fig. 3.1.

Assume that there are no resistive forces opposing the motion of the block. The block hits a spring and decelerates. The speed of the block becomes zero when the compression of the spring is 8.0 cm.

Calculate the initial kinetic energy of the block.