m = Mass of the refrigerator to be moved to third floor = 136 kg
g = Acceleration due to gravity by earth on the refrigerator being moved = 9.8 m/s²
h = Height to which the refrigerator is moved = 8 m
W = Work done in lifting the object
Work done in lifting the object is same as the gravitational potential energy gained by the refrigerator. hence
Work done = Gravitation potential energy of refrigerator
W = m g h
inserting the values
W = (136) (9.8) (8)
W = 10662.4 J
Answer:
They will move the fridge if they all push in the same direction, but it will not move with constant velocity
Explanation:
The maximum static friction force is
(negative sign since its direction is opposite to the push applied by the people)
Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:

This force is larger than the frictional force, so the fridge will start moving.
However, the net force on the fridge will be:

And according to Newton's second law,

where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.
What gas? Gas is an invisible form so I don't see how it would have a "defined structure".
It comes from the sun, and then it is converted to energy/electricity (by solar panels)
Answer:
The length of chain she is allowed is 1.169 ft
Explanation:
The given parameters are;
The linear density of the chain = 0.83 lb/ft
The weight limit of the chain she wants = 1.4 lb
The formula for linear density = Weight/length
Therefore, in order to keep the chain below 1.4 lb, we have;
Linear density = Weight/length
Therefore;
The maximum length she wants = Weight/(Linear density)
Which gives;
The maximum length she wants = 1.4 lb/(0.83 lb/ft) =1.169 ft
Therefore;
The length of chain she is allowed = 1.169 ft.