A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock 1 is thrown vertically upward, rock 2 is thrown vertically downward, and rock 3 is thrown horizontally. Assuming the elevation loss of the three rocks is the same (the base of the cliff is flat), which rock hits the ground with the highest speed (= magnitude of velocity)?
Rock 2
Rocks 1 and 2
Rocks 2 and 3
Rock 3
They all hit the ground with the same speed.
Rocks 1 and 3
Rock 1