A girl on her bicycle rides in a direction opposite of her dad, who is driving away in his car at 33.4 m/s . The girl's speed is 8.54 m/s as she rings the bell on her bike . her dad hears a 714Hz ringing sound , what is the frequency of the girl's bell ?

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)