Estimate the power required by a toy-fish cruising horizontally at 5 km/h in seawater. The shape of the fish can be approximated as an ellipse with 5 cm major axis, 2.5 cm minor axis, and 10 cm width.

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.