A police car is moving east at 20m/s towards a driver who is moving west at 25m/s. The police car emits a frequency of 900Hz. What frequency is detected by the driver? The speed of sound at the time of this occurrence was 343m/s.

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is as it changes into other forms of energy.

Aperson touches a large chunk of ice with their hand and remarks, “this is making me cold.” explain what this person is feeling. is the ice transferring “cold” to the person? is there a heat transfer occurring? explain.

Asailboat is traveling to the right when a gust of wind causes the boat to accelerate leftward at 2.5m/s2 for 4s. after the wind stops, the sailboat is traveling to the left with a velocity of 3.0m/s. assuming the acceleration from the wind is constant, what was the initial velocity of the sailboat before the gust of wind? answer using a coordinate system where rightward is positive.