Question

For the following problems consider a person throwing a ball straight up, and then letting it fall down. Ignore wind resistance.
7. Describe the velocity of the ball the moment it is released from the hand.
A. Positive Velocity
B. Negative Velocity
C. No Velocity
8. Describe the velocity of the ball when it is at the highest point.
A. Positive Velocity
B. Negative Velocity
C. No Velocity
9. Describe the velocity of the ball when it is about to reach the ground
A. Positive Velocity
B. Negative Velocity
C. No Velocity
10. What does constant velocity tell us about a situation.

Answer 1

Hmmm well positive or negative velocity depends on the direction u have chosen to be positive

Answer 2

If the upwards direction is positive then upwards velocity will be positive

Answer 3

At the highest point of the path during motion under gravity the velocity become zero for a short interval of time because as the object moves upward the gravity acts on the object downward which in result decrease velocity of object

Answer 4

7A. It depends, though, on which direction the velocity vector is taken as positive. Being a postive sort of bird of prey, though, I'll take that UP is positive
9B What goes UP SHOULD COME DOWN. Unless, of course, it's a space rocket etc etc etc.
10 constant velocity tells you that all the forces that COULD be acting on something ARE BUT they're BALANCED and the thing is just moving at, well, constant velocity. Classic example of this is TERMINAL velocity on, say raindrops, and why they don't kill you when it rains having fallen from the HIGH SKIES.
bon chance et bon voyage
http://perendis.webs.com