n earthquake emits both P-waves and S-waves that travel at different speeds through the Earth. A P-wave travels at 9 000 m/s and an S-wave at 4 000 m/s. If P-waves are received at a seismic station 34.0 s before an S-wave arrives, how far is the station from the earthquake center

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)