PROBLEM 2.27 A girl is riding her bicycle. When she gets to a corner, she stops to get a drink from her water bottle. At that time, a friend passes by her, traveling at a constant speed of 10.0 m/s. 32. After 25 s, the girl gets back on her bike and travels with a constant acceleration of 2.5 m/s2. How long does it take for her to catch up with her friend? c. 20.70 s d. 21.70 s а. 19.70 s b. 18.70 s 33. If the girl had been on her bike and rolling along at a speed of 1.5 m/s when her friend passed, what constant acceleration would she need to catch up with her friend in the same amount of time? c. 0.709 m/s² d. 0.609 m/s² а. 0.809 m/s² b. 0.909 m/s²

4) You were leisurely flying your F-18 when you encounter an alien aircraft. The alien was flying at an altitude of 3 km while you were at an altitude of 600 m. You begin to increase your speed at a rate of 2.0 m/s?. You are traveling at a speed of 750 km/h at the instant when 0 = 45° and at the same instant the alien has a constant velocity of 1,500 km/h. a) Determine the velocity and acceleration vectors (in m/s and m/s², respectively) of the alien as observed by you. [Ans. to Check: VB/A = 208.4 įm/s] b) Determine the time rate of change of the vector r that is between you and the alien ship in m/s. In other words, find r. [Ans. to Check: i = 147.32 m/s] Hint: Do not forget about your ability to dot in different directions to eliminate variables from the equation. c) Calculate the angular velocity of the spaceship relative to you in rad/s. d) Determine the radial and angular accelerations in m/s? and rad/s². [Ans. to Check: ï = 4.86 m/s²] VB 3 km VA 600 m