When an ambulance passes by, the siren’s pitch changes. The sounds becomes higher-pitched as it approaches, and then the pitch lowers as it gets further away. This change in pitch is known as the Doppler effect. What causes this change in pitch? A. The waves emitted by an object moving toward an observer are squeezed closer together, and frequency appears to increase.
B. The waves emitted by an object moving away from an observer are squeezed closer together, and frequency appears to increase.
C. The waves emitted by an object moving toward an observer are stretched farther apart, and frequency appears to decrease.
D. The waves emitted by an object moving toward an observer are stretched farther apart, and frequency appears to increase.

We want to calculate the total metabolic heat generated by a singing canary taking into account heat transfer by radiation, convection and exhaling air. the air temperature is 20 oc, canary’s body internal and surface temperature is 33oc, external body surface convective heat transfer coefficient is 25.2 w/m2 .k, temperature difference between the inhaled and exhaled air is 4.3 oc, the ventilation rate is 0.74 cc of air per second, specific heat of air is 1.0066 kj/kg.k and density of air is 1.16 kg/m3 . assume the canary’s body to be a cylinder with 7 cm diameter and 9 cm length, and heat exchange is from the side as well as the top and bottom of cylinder. calculate 1) the net rate of heat lost by radiation, assuming heat gained by the bird through radiation from the surroundings is 11.5 w; 2) rate of heat transferred by convection to the surrounding air; 3) rate of heat transferred in the exhaling air without considering any internal evaporation; 4) total metabolic power.

Ms.hidalgo opens the door to her classroom. her classroom is 60 degrees and the air outside is 80. predict what will happen using your knowledge of how heat flows.

In science and physics what is the standard unit of measure for speed?