Why is the force to double acceleration not double the applied force?

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance. what is its vertical displacement (in m) after 6 s?

Simple machines can a. increase force only b. decrease force only c. increase or decrease force

Waves that cause the most damage during an earthquake are a. surface waves c. s waves b. p waves d. ocean waves