For which optical devices does d¡ always have a negative value? A. A and B
B. A and D
C. Band D
D. B and C

12. a body is a particular amount of matter. it can be a solid, liquid or gas. it can be described as existing in a. size and shape. b. motion and force c. time and space. d. location and movement.

Abasketball star covers 2.65 m horizontally in a jump to dunk the ball. his motion through space can be modeled precisely as that of a particle at his center of mass. his center of mass is at elevation 1.02 m when he leaves the floor. it reaches a maximum height of 1.90 m above the floor and is at elevation 0.910 m when he touches down again. (a) determine his time of flight (his "hang time"). (b) determine his horizontal velocity at the instant of takeoff. (c) determine his vertical velocity at the instant of takeoff. (d) determine his takeoff angle. (e) for comparison, determine the hang time of a whitetail deer making a jump with center-of-mass elevations yi = 1.20 m, ymax = 2.45 m, and yf = 0.750 m.

An experiment was performed on a 2-kg block. forces of 5, 10 and 15 newtons respectively were applied to the block for 5 seconds. describe the difference in acceleration between the three trials. a) the final accelerations will all be the same. b) the final acceleration will triple between the first and third trial. c) the final acceleration will be cut by 1/3 from the first to third trial. d) the final acceleration will increase nine time between the first and third trial.