Definitions 9. For each circumstance, below, describe a situation in which it can happen. Write "N/A" if it is not possible, and explain why. (a) velocity, v , is not constant and speed, v , is constant (not 0) (b) speed is not constant and velocity is constant (not 0) (c) displacement, A x , is constant (not 0) and acceleration, a , is constant (not 0) (d) acceleration, a , is not constant (not 0), acceleration, a , is constant (e) displacement, A s , is constant (not 0), and velocity, v , is not constant. 10. An object's motion at a moment in time is described by four cases below. (a) a=+2mls'i, v=+5mlsi, s=+3mi (b) a=-2mls'i, v=+5mlsi, s=+3mi (c) a=+2mls'i , v=-5mlsi, s=-3mi (d) a=-2mls'i, v=-5mlsi, s=-3mi where a = acceleration, v = velocity, and s = position. [Note: Each case should appear once in one of the slots. Despite what some students claim, for example, it is impossible for this object to speed up and to slow down at the same.] (a) In which case(s) is (are) the object in the process of speeding up? (b) In which case(s) is (are) the object in the process of slowing down? (c) In which case(s) is (are) the object not in the process of changing its speed? 11. Greg is driving a car to our right, sees the light is red, slams on his brakes, and skids toward the light (in a straight line). (a) While skidding, what is the direction of the car's velocity? (b) What is the direction of the car's acceleration, a ? 12. When are position and displacement interchangeable? 13. When is average speed the same as the magnitude of average velocity? Graph 14. Describe the motion necessary to create the displacement graphs. Displacement vs. Time Displacement (m) 0 0 1 2 3 5 6 7 Time (s) a)