The double number line below shows the approximate number of kilograms in a certain number of pounds: two number lines are shown one above the other. the number line on the top shows three longer vertical lines. between each longer vertical line there is a shorter vertical line. there is one shorter vertical line after the last longer vertical line. there by making a total of three shorter vertical lines. the longer vertical lines are labeled 11, 13, 15. on the right of this number line is written pounds. the number line below it also has three longer vertical lines and three shorter vertical lines. the first longer vertical line is ahead of the first longer vertical line of the top number line so that the first shorter vertical line on the lower number line is aligned with the first longer vertical line, labeled 11 on the top number line. the second longer vertical line is ahead of the second longer vertical line of the top number line so that the second shorter vertical line on the lower number line is aligned with the second longer vertical line, labeled 13, on the top number line. the third longer vertical line is ahead of the third longer vertical line of the top number line so that the third shorter vertical line on the lower number line is aligned with the third longer vertical line, labeled 15, on the top number line. the longer vertical lines on the bottom number line are labeled 5, 6, 7, respectively. on the right of this number line is written kilograms. based on the number line, about how many kilograms are there in 17 pounds?

Airplane speeds are measured in three different ways: (1) indicated speed, (2) true speed, and (3) ground speed. the indicated airspeed is the airspeed given by an instrument called an airspeed indicator. a plane’s indicated airspeed is different from its true airspeed because the indicator is affected by temperature changes and different altitudes of air pressure. the true airspeed is the speed of the airplane relative to the wind. ground speed is the speed of the airplane relative to the ground. for example, a plane flying at a true airspeed of 150 knots into a headwind of 25 knots will have a ground speed of 125 knots. the problems below refer to static and dynamic pressure. static pressure is used when a body is in motion or at rest at a constant speed and direction. dynamic pressure is used when a body in motion changes speed or direction or both. a gauge compares these pressures, giving pilots an indicated airspeed. in problem #s 1 and 2, use the following information. the indicated airspeed s (in knots) of an airplane is given by an airspeed indicator that measures the difference p (in inches of mercury) between the static and dynamic pressures. the relationship between s and p can be modeled by s=136.4p√+4.5. 1. find the differential pressure when the indicated airspeed is 157 knots. 2. find the change in the differential pressure of an airplane that was traveling at 218 knots and slowed down to195 knots. in problem #s 3 and 4, use the following information. the true airspeed t (in knots) of an airplane can be modeled by t=(1+a50,000) ⋅ s, where a is the altitude (in feet) and s is the indicated airspeed (in knots). 3. write the equation for true airspeed t in terms of altitude and differential pressure p. 4. a plane is flying with a true airspeed of 280 knots at an altitude of 20,000 feet. estimate the differential pressure. explain why you think your estimate is correct.

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

The moats separating people from the animals are 5 m wide for lions and 4 m wide for the elephants. if the lion’s moat is 4 m deep, how deep should the elephants’ moat be?