Atruck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction. if the frequency of the siren is 500 hz relative to the police car, what is the change in frequency (in hz) heard by an observer in the truck as the two vehicles pass each other?

Alarge cruise ship of mass 7.00 ✕ 107 kg has a speed of 11.6 m/s at some instant. (a) what is the ship's kinetic energy at this time? (b) how much work is required to stop it? (give the work done on the ship. include the sign of the value in your answer.) (c) what is the magnitude of the constant force required to stop it as it undergoes a displacement of 3.00 km?