A motorcyclist ( as a particle ) is undergoing vertical circles inside a sphere of death . the speed of the motorcycle varies between 6 m/s and 10 m/s . calculate diameter of the sphere of death . how much minimum values are possible for these two speeds ?

Explanation:

v=6+10/2=8m/s

(F=Mg)

Mg=Mv×v/r

r=v×v/g

r=8×8/10

r=6.4

so diameter=6.4×2=13.8m

(I think this is correct answer)

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )