please help

86. While driving at an average velocity of 15.6 m/s down the road, a driver slams on the brakes to avoid hitting a squirrel. The car stops completely in 4.2 seconds. What is the average acceleration of the car?

87. A sports car is advertised as being able to go from 0 to 60 in 6.00 seconds. If 60 mi/h is equal to 27 m/s, what is the sports car's average acceleration?

88. If a bicycle has an average acceleration of -0.44 m/s², and its initial forward velocity is 8.2 m/s, how long will it take the cyclist to bring the bicycle to a complete stop?

89. An airliner has an airborne velocity of 232 m/s. What is the plane's average accel- eration if it takes the plane 15 minutes to reach its airborne velocity?

90. A school bus can accelerate from a com- plete stop at 1.3 m/s². How long will it take the bus to reach a velocity of 12.1 m/s?​