Answer:
c. Kinetic energy is conserved in all collisions .
Explanation:
the total kinetic energy of system of particles involved in the collision does changes .
kinetic energy is not conserved in all collisions because in some cases energy is converted to another form of energy that is heat etc .
Answer : The temperature of the hot reservoir (in Kelvins) is 1128.18 K
Explanation :
Efficiency of carnot heat engine : It is the ratio of work done by the system to the system to the amount of heat transferred to the system at the higher temperature.
Formula used for efficiency of the heat engine.

where,
= efficiency = 0.780
= Temperature of hot reservoir = ?
= Temperature of cold reservoir = 
Now put all the given values in the above expression, we get:



Therefore, the temperature of the hot reservoir (in Kelvins) is 1128.18 K
Answer: c
Explanation: hope this helps :)
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