A "sandwich" is constructed of two flat pieces of metal (0.70 cm on a side) with a 1.0-mm-thick piece of a dielectric called rutile (K 100) in
between them. What is the capacitance? (E0 = 8.85 x 10-12C/N m)
43 pF
4.3 nF
8.85 uF
6.2 pF
0.62 nF

The anwser is: wave a has a greater pitch and frequency.

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.