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An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

How do we measure or think of speed in the united states?