The illuminance on a surface is 6 lux and the surface is 4 meters from the light source. what is the intensity of the saurce?

Match the atomic particles with their characteristics. 1. made of two protons and two neutrons neutron 2. similar to an electron; positive charge neutrino 3. orbits nucleus; negative charge positron 4. bundle of energy; zero charge proton 5. found in nucleus; positive charge meson 6. very unstable; +, -, or zero charge gamma 7. found in nucleus; zero charge electron 8. negative particle; negative charge beta 9. atomic energy converted to mass alpha

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?

Apulley with mass mp and a radius rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot.