A real question, one with a question mark?
True, they have zero electrical resistance.
Answer:
Explanation:
Given
mass of boy=36 kg
length of swing=3.5 m
Let T be the tension in the swing
At top point 
where v=velocity needed to complete circular path
Th-resold velocity is given by 

So apparent weight of boy will be zero at top when it travels with a velocity of 
To get the velocity at bottom conserve energy at Top and bottom
At top 
Energy at Bottom 
Comparing two as energy is conserved



Apparent weight at bottom is given by

Answer:
the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Explanation:
Given;
diameter of the ceiling fan, d = 90 cm = 0.9 m
angular speed of the fan, ω = 64 rpm
time taken for the fan to stop, t = 28 s
The distance traveled by the ceiling fan when it comes to a stop is calculated as;

The speed of the tip of a blade 10 s after the fan is turned off is calculated as;

Therefore, the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Gravitational potential energy = mgh or mass times acceleration due to gravity times the height
Here the mass is 0.25kg, the height is 10m, and gravity is 9.8m/s^2 so...
GPE = (0.25)(10)(9.8)
GPE = 24.5 J