Example 30.9. A locomotive draws a train of mass 400 tonnes, including its own mass, a a level ground with a uniform acceleration, until it acquires a velocity of 54 km. p.h in 5 minutes. If the frictional resistance is 40 newtons per tonne of mass and the air resistance varie with the square of the velocity, find the power of the engine. Take air resistance as 500 newtons at 18 km. p.h.

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.