The 3000-lb load is applied to wedge B. The coefficient of static friction between A and C and between B and D is 0.3, and between A and B it is 0.4. Assume the wedges have negligible weight. Find: The smallest force P needed to lift 3000 lb load.

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?