Mr. richard's science class is conducting a variety of experiments with projectiles and falling objects. two groups of students are using a slingshot to launch tennis balls from ground level, and two groups are dropping tennis balls from the fire escape. below are descriptions of the parameters with which each group launches or drops their tennis balls. group a launches a tennis ball straight up with an initial velocity of 19 meters per second. group b launches a tennis ball straight up with an initial velocity of 50 feet per second. group c drops a tennis ball from a height of 19 meters. group d drops a tennis ball from a height of 50 feet. determine which group's activities can be modeled by the following equations, where h is the current altitude of the tennis ball. 1. h = -4.9t^2 + 19. (a-b-c-d) 2. h = -16t^2 + 50t. (a-b-c-d) 3. h = -16t^2 + 50. (a-b-c-d) 4. h = -4.9t^2 + 19t. (a-b-c-d)

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

An annual marathon covers a route that has a distance of approximately 26 miles. winning times for this marathon are all over 2 hours. the following data are the minutes over 2 hours for the winning male runners over two periods of 20 years each. earlier period 14 12 15 22 13 10 19 13 9 14 20 18 16 20 23 12 18 17 6 13 recent period 7 11 7 14 8 9 11 14 8 7 9 8 7 9 9 9 9 8 10 8 (a) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the earlier period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks. for more details, view how to split a stem.) minutes beyond 2 hours earlier period 0 1 2 (b) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the recent period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks.) minutes beyond 2 hours recent period (c) compare the two distributions. how many times under 15 minutes are in each distribution

Which value of y will make the inequality y< -1 false?