Which of the following correctly describes the importance of demonstrations to a scientific investigation?
a. in a demonstration, empirical data is collected.
b. a demonstration is a process involving scientific investigation.
c. in a demonstration, the effect of one thing on another is measured.
d. a demonstration shows how something works, often including models.

Adelivery truck leaves a warehouse and travels 2.60 km north. the truck makes a left turn and travels 1.25 km west before making another right turn to travel 1.40 km north to arrive at its destination. what is the magnitude and direction of the truck's displacement from the warehouse?

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.

Asap time is ! best answer gets compose at least one well-developed paragraph on the following: define the term concurrent powers, and give an example of a concurrent power of government.