Answer:
Time taken, 
Explanation:
It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.
From the figure,
The sum of forces in y direction is :


Sum of forces in x direction,

.............(1)
Also, 
Equation (1) becomes :

...............(2)
Let t is the time taken for the ball to rotate once around the axis. It is given by :

Put the value of T from equation (2) to the above expression:


On solving above equation :

Hence, this is the required solution.
A male having the disease.
Answer:
3.71 m/s
Explanation:
From the law of conservation of linear momentum, since we are neglecting minor energy losses due to friction then we can express it as
since all the potential energy is transformed to kinetic energy
Making v the subject of the formula then
and here m is the mass of the block, g is acceleration due to gravity, h is the height. Substituting 0.7 m for h and 9.81 for g then we obtain that
D only kinetic energt because if it had heluim or any thing jt will float up