Answer:
581 kJ, work was done by the system
Explanation:
According to the first law of thermodynamics:

where
is the change in internal energy of the system
Q is the heat absorbed by the system (positive if absorbed, negative if released)
W is the work done by the system (positive if done by the system, negative if done by the surrounding)
In this problem,


Therefore the work done by the system is

And the positive sign means the work is done BY the system.
Answer: D
Explanation: there is less light at that point.
Answer:
0.231 N
Explanation:
To get from rest to angular speed of 6.37 rad/s within 9.87s, the angular acceleration of the rod must be

If the rod is rotating about a perpendicular axis at one of its end, then it's momentum inertia must be:

According to Newton 2nd law, the torque required to exert on this rod to achieve such angular acceleration is

So the force acting on the other end to generate this torque mush be:

Answer:
Gravity, Friction, Air resistance, magnetism, static electricity
Explanation: