Q. A group of swimmers is resting in the sun on an off-shore raft. They estimate that 4.8 m separates a trough and an adjacent crest of surface waves on the lake. They count 16 crests that pass by the raft in 13 s. How fast are the waves moving?
Q. Two resistances, R1 and R2, are connected in series across a 12-V battery. The current increases by 0.23 A when R2 is removed, leaving R1 connected across the battery. However, the current increases by just 0.11 A when R1 is removed, leaving R2 connected across the battery. Find (a) R1 and (b) R2.