A motorcycle is moving with a velocity of 140 km/h. The driver applied brake for 6 seconds to bring it down to zero. What is the average acceleration? Is it decelerating? YES OR NO? O a. -6.48 m/s2 and YES O b. -23.33 m/s and NO O c. -38.89 m/$2 and YES O d. -38.89 m/s and YES O e. 6.48 m and NO Of. -23.33 m/s2 and YESAs an engineer, you were asked to design a runway for an airport. An airplane that will use this airfield must reach a certain velocity in 20 s before take-off and should accelerate at 4 m/s2. 1. What will be the velocity of the airplane after 20s? 2. What must be the minimum length of the runway? O a. vf=80m and d=400m/s O b. vf= 1600m/s and d= 320m O c. vf= 80m/s and d= 800m O d. vf= 320m/s and d= 1600m O e. vf= 800m/s and d= 80m Of. vf=400m/s and d= 80m