Help. Please explain to me how you got the answer.

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge

Tafari worked one summer on a ship that set weather buoys in the ocean. he watched how one of the buoys moved in the water. describe which parts of the wave would cause the buoy to bob up and down. which wave property determined how fast the buoys bobbed in the water? he observed that when the wind blew harder, the ocean waves were larger, and the buoys moved away from the ship. what effect, if any, did the waves have on how far the buoys moved? explain your answer.

The bar of prob. 5/82 is repeated here. the ends of the 0.4-m bar remain in contact with their re- spective support surfaces. end b has a velocity of 0.5 m/s and an acceleration of 0.3 m/s2 in the di- rections shown. determine the angular accelera- tion of the bar and the acceleration of end a.