PLEASE HELP ASAP In this diagram you see a wave. B is at the high point of the wave; D is at the low point in the wave. A, D, and E are located where the wave crosses the t-axis.

Which letter represents the trough of the wave?

1. explain how you calculate the net force in any direction on the box. 2. suppose an upward force of 15n is added to the box. what will be the net vertical force on the box? 3. what force could be applied to the box to make the net force in the horizontal direction zero? explain. 4. suppose a force of 25n to the right is added to the box. what will be the net force to the right?