Question

If kinematics can give you data on a dropped object, would it be valid to use kinematics to calculate the acceleration experienced by the object upon impact with the ground? (the time from when it hits the ground to when it actually stops)

Answer 1

When the object hits the ground until its velocity reaches
zero is some time, call it t. Its
momentum drops from mv (where m is the
mass and v is the speed when it hits) to zero
because an impulse I was delivered to it by the
ground. The impulse may be written as I=Favgt.
where Favg is the average
force. Therefore you can find the average acceleration aavg
during the collision, but not the acceleration as a function
of time: aavg=Favg/m=I/(mt)=v/t.
So you cannot get detailed kinematics about the
collision without measuring how the speed decreases with
time.