Answer:

Explanation:
initially the merry go round is at rest
after 6.73 s the merry go round will accelerates to 20 rpm
so final angular speed is given as



so final tangential speed is given as


now average acceleration of the girl is given as



Answer:
The current is
Explanation:
From the question we are told that
The radius of the loop is 
The earth's magnetic field is 
The number of turns is 
Generally the magnetic field generated by the current in the loop is mathematically represented as

Now for the earth's magnetic field to be canceled out the magnetic field generated by the loop must be equal to the magnetic field out the earth

=> 
Where
is the permeability of free space with value 

=> 

I have no idea what you are trying to ask sorry
Answer:

Explanation:
Given data:
weigh (head+arms + head) w_1 = 438 N
centre of gravity y_1= 1.28 m
weigh (upper leg) w_2 = 144 N
Center of gravity y_2 = 0.760 m
weigh ( lower leg + feet) = 87 N
centre of gravity = y_3 = 0.250 m
location of center of gravity 

