g What is the final velocity of a hoop that rolls without slipping down a 6.92 m high hill, starting from rest

The value is  

Explanation:

From the question we are told that

  The height of the hill is  

Generally from the law of energy conservation we have that

Here  PE is the potential energy of the hoop which is mathematically represented as

 KE is the kinetic energy of the hoop  which is mathematically represented as

And  

  RKE  is the rotational  kinetic energy which is mathematically represented as

Here I  is the moment of inertia of the hoop which is mathematically represented as

and  w  is the angular velocity which is mathematically represented as

So

=>    

So

=>  

=>  

=>  

d. platinum would have the greatest temperature increase because it has the lowest specific heat.