Answer:

Explanation:
Using the tension in the spring and the force of the tension can by describe by
T = kx
, T = mg
Therefore:

With two springs, let, T1 be the tension in each spring, x1 be the extension of each spring. The spring constant of each spring is 2k so:


Solve to x1





The kinetic energy is

and the height of the building doesn't matter at all.

joules
Answer:
speed and direction
Explanation:
Acceleration is the rate of change of speed and direction.
Answer:
C) is zero
Explanation:
According to the law of energy conservation, the total mechanical energy of the object is conserved. A book falling a distance d would have a change in potential energy, resulting in the same change in kinetic energy. But the total mechanical energy must be the same. So there's 0 change in total energy of the system.