An object with initial velocity 1.8m/s moves along a line with constant acceleration and travels 800m in 40sec. What is the acceleration in m/s2 ? Your Answer: Answer Question 12 ( 1.5 points) A stone is thrown straight downward with certain initial speed from a height of 99.9m. If the stone land the ground after 3.25sec, what was the initial speed of the stone? Your Answer: Answer Question 13 (1 point) You drop a stone into a 300 meter deep well. How long after you will hear the sound of hitting? Sound velocity is given 334 m/s