Which of the following statements about ohm’s law is true?
a. to increase the current, decrease the resistance.
b. keeping the same voltage and decreasing resistance decreases the current.
c. ohm’s law relates power, current and resistance.
d. increasing the voltage decreases current if resistance stays the same.

One of the things that Ohm's law suggests is that the current in
a circuit is inversely proportional to the resistance in the circuit. 

That's what choice-A says ... if the resistance decreases, then
the current will increase.

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.

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.