physics
posted by todd on .
Take the mass of the Earth to be 5.98 ×
1024 kg.
If the Earth’s gravitational force causes a
falling 52 kg student to accelerate downward
at 9.8 m/s2, determine the upward accelera
tion of the Earth during the student’s fall.
Answer in units of m/s2.

The same force acts on each mass
massstudent*g=massEarth*a
solve for a.