W = m · g · h
h = 28.3 m · sin 45° = 28.3 m · 0.707 = 20 m
g = 9.8 m/s²
W = 75 kg · 9.8 m/s² · 20 m
Answer:
W = 14,700 J = 14.7 kJ
Answer:
(a) 
(b) 
Solution:
As per the question:
Mass of the object, m = 1.30 kg
Length of the rod, L = 0.780 m
Angular speed, 
Now,
(a) To calculate the rotational inertia of the system about the axis of rotation:
Since, the rod is mass less, the moment of inertia of the rotating system and that of the object about the rotation axis will be equal:

(b) To calculate the applied torque required for the system to rotate at constant speed:
Drag Force, F = 

Electric force from electomagnetic force and force of gravity from gravitational force