The velocity of a rotary tidal current will...

The velocity of a rotary tidal current will be decreased when the Moon is at which phase?

🔍 Key Concepts

• Tidal currents are stronger or weaker depending on the gravitational pull of the Moon and Sun • The phase of the Moon (new vs full vs quarters) changes how the Moon and Sun’s gravity combine • The Moon’s distance from Earth (apogee vs perigee) changes how strong its gravitational pull is

💭 Think About

• Ask yourself: in which situation are tidal ranges and currents at their strongest (spring tides), and in which are they at their weakest (neap tides)? • Separate in your mind: phases (new/full) vs distances (apogee/perigee). Which of these pairs is mainly about alignment with the Sun, and which is mainly about distance and gravity strength? • Think about whether decreased current speed would be linked to smaller tidal range or larger tidal range.

✅ Before You Answer

• Identify which conditions produce spring tides (strongest currents) and which produce neap tides (weakest currents) • Recall that apogee = Moon farthest from Earth, perigee = Moon closest to Earth • Match the choice that corresponds to a situation where the gravitational pull is weaker, leading to smaller tidal ranges and slower rotary tidal currents