A 5 kg mass initially falling with a speed of 3m/s is later falling with a speed of 23 m/ s. How much time did it take for its speed to change?

1. do the particles in the medium material move in the same direction of the wave or at opposite direction to the wave? explain your answer. 2. by inputting more energy into the wave, i.e a large shake of the spring, which wave property also increases? 3. are there forces of friction acting while a wave is passing through a medium?