Answer:
a)
, b) 
Explanation:
a) The equation for vertical velocity is obtained by deriving the function with respect to time:

The velocities at given instants are, respectivelly:


Hot spots are fixed locations in the earth's mantle where heat from the earth's interior rises to the surface and produces volcanism. the earth's plates, which are slowly but constantly moving, are pierced by the uprising magma. as they move away form the hotspot, the volcanoes become dormant and are replaces by new volcanoes. The direction of the line formed from the previous volcanoes indicates the direction :)))
what are the answer choices?
The sound wave never actually loses energy, the bulk of energy it had at the beginning of the sound, is spread out into a sphere, making it decrease in amplitude and frequency.