PLEASE HELP For this problem, use g = -9.8 m/s2. vi for the bag = velocity of the helicopter (including the sign). Use the point where the bag is dropped as yi = 0. Final values for this problem are when t = 2.
a) What is vf for the mailbag?
b) What is yf for the helicopter? vh = constant.
c) What is yf for the mailbag? vm ≠ constant.
d) How far below the helicopter is the mailbag?
Now repeat the problem for the helicopter ascending with vih = 1.5 m/s.
e) What is vf for the mailbag?
f) What is yf for the helicopter? vh = constant.
g) What is yf for the mailbag? vm ≠ constant.
h) How far below the helicopter is the mailbag?

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?

The seven sisters, seven stars located more than 400 light-years away in the taurus constellation can be seen here with venus and another constellation, orion. the seven stars stay grouped together but seem to move, like the planet venus. why do stars seem to move like planets in the night sky?