【单选题】An object is dropped from a bridge. A second object is thrown downwards 1.00 s later. They both reach the water 20.0 m below at the same instant. What was the initial speed of the second object?
【简答题】What was the engineers ’ primary goal? A . To develop a car superior to the initial model. B . To put super sports cars into mass production. C . To learn how to make a sports car by themselves.