You are out and about in the country and your father sees a rock that he really wants in the yard. now you must get the very heavy rock into the back of a truck. the truck bed is 3 feet off the ground. your father pulls out a 5-foot plank and begins to set up a ramp. at the same time, you (who know about mechanical advantage! ) have found a plank that is 8 feet long, and you show it to your father.

which plank will give you the most mechanical advantage? calculate the ma for each plank.

me ! < 3

The metal wire in an incandescent lightbulb glows when the light is switched on and stops glowing when it is switched off. this simple process iswhich kind of a change? a. a physical changeb. a chemical changec. a nuclear changed. an ionic change

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?