A police siren has a frequency of 340.0 Hz when the car is stationary and the temperature is 20°C. The police car at point S moves to the right with a speed of 22.0 m/s. a. What frequency does observer A hear?
b. What frequency does observer B hear?
c. Suppose observer A is moving toward the stationary police car. What is the speed of observer A if the frequency heard is 369 Hz?

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?

If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 380j of energy to the room?