Joke Collection Website - Bulletin headlines - On May Day, Xiao Jia and his classmates went to the playground to play the big Ferris wheel. The radius of Ferris wheel is 20m, and it takes 12 minutes to rotate at a constant speed.

On May Day, Xiao Jia and his classmates went to the playground to play the big Ferris wheel. The radius of Ferris wheel is 20m, and it takes 12 minutes to rotate at a constant speed.

Figure: BD=AD-AB=30.5-0.5=30

∴OD=BD-OB=30-20= 10

∵OD⊥MN

∴MD=ND

∴:od = 10, ON=20 in Rt△ODN.

OD= 1/2ON

∴∠DNO=30

∴∠NOD=60

∴∠MON=2∠NOD= 120

∫ Bad arc MN/ perimeter = 120/360= 1/3

∴ During the rotation of the Ferris wheel, the time for Jony J to stay in the air at least 30.5m above the ground continuously = 12× 1/3 = 4 minutes.