As friends frequently do, Josh and John stand at either end of a very long, stationary skateboard, with Josh at the front and John at the rear. John then tosses a heavy ball toward Josh who, caught unawares, ducks so that the ball goes sailing over his head and lands on the ground. There is no friction between the skateboard and the ground. After the ball is thrown, which way, if at all, does the skateboard move

A. Backward
B. Forward
C. Neither

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.

9.98 kg of r-134a at 300 kpa fills a rigid container whose volume is 14 l. determine the temperature and total enthalpy in the container. the container is now heated until the pressure is 600 kpa. determine the temperature and total enthalpy when the heating is completed. use data from the steam tables.

When using the scientist method, which step comes last?