What is the phenomenon of sound waves changing when an emergency vehicle's siren is approaching and then going away from you? Blank 1:

Ice at 0.0∘c has a density of 917 kg/m3. a 3.00 cm3 ice cube is gently released inside a small container filled with oil and is observed to be neutrally buoyant. what is the density of the oil?

Asquare isothermal chip is of width w=5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at tinf=15 °c. from reliability considerations, the chip temperature must not exceed t=85 °c. if the coolant is air and the corresponding convection coefficient is h=200 w/m2 x k, what is the maximum allowable "power" of the chip? if the coolant is a liquid for which h=3000 w/m2 x k, what is the maximum allowable power of the chip?

Hi , i am new here can anyone me out with this question why is space black after having so many shining objects like sun , moon , stars