You will see a diagram with several lettered locations. You are given the speed at location A. You want to know at which location will the object be moving upward with a speed of 10 m/s. To do so, you need to know at least two things:
- A free-falling object accelerates downward with an acceleration of approximately -10 m/s/s.
- The vertical velocity of the object is changing by -10 m/s for every second of motion.
The lettered dots on the diagram represent the location at 1-second intervals. So beginning at location A (where the speed is known), go dot by dot through the diagram. Subtract 10 m/s each time you arrive at a new dot on the diagram until you get to 10 m/s. There will be two such locations - one on the first half of the trajectory and the other on the second half of the trajectory. Since the question states that the object is moving upward at 10 m/s, you will need to pick the first of these two points. The location on the upward side of the trajectory where the velocity becomes 10 m/s is the answer to this question.