A constant horizontal force of 21 N pushes a 30 kg-mass through a medium that resists its motion with 0.7 N for every m/s of speed. The initial velocity of the mass is 7 m/s in the direction opposite to the direction of the applied force. Find the velocity of the mass after 30 seconds.

The magnitude of the poynting vector of a planar electromagnetic wave has an average value of 0.939 w/m^2 . the wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. how much total electromagnetic energy falls on the area during 1.0 minute?

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c

Apropagating wave in space with electric and magnetic components. these components oscillate at right angles to each other. it may travel in a vacuum. determine the term.