Final answer:
Longshore currents are influenced by the speed of water flow, ocean floor topography, shoreline shape, wind patterns, tidal variations, and the density of the water. These factors combined contribute to the current's strength and speed.
Step-by-step explanation:
The variables that affect the speed of longshore currents are mostly related to the environmental conditions and physical characteristics of the water and the nearshore zone. One key factor is the speed of water flow, which includes both the velocity of the waves approaching the shore and the rate at which water moves along the shore. Another is the impact of the ocean floor topography and the shoreline's shape, which can alter the flow and speed of the current. Additionally, environmental factors such as wind patterns and the presence of tidal variations also play a role. It's also worth mentioning that the density of the water affects how much energy is transferred from the wind to the water, subsequently influencing the longshore current's speed.