Explain your answer pls 1. Why do we exist?

2. How and why doesn’t all humanity all die right now?

Which of the following statements does not explicitly describe a transfer of money a. a ball dropped from a heigh hits the ground with a high speed. b. the collision produced in a nuclear reaction heat up the surroundings. c. a plane increases its air speed from 150 mi/hr to 200 mi/hr. d. the electricity from the power socket causes the fan to turn.

An ideal spring has a spring constant (force constant) of 2500 n/m, is stretched 4.0 cm, how much elastic potential energy does it possess? (a) 3j (b) 0.00j (c) 1j (d) 2j (e) 4j

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.