B because the skater is constantly moving in the same speed to go in a circle .
The circuit change when a wire is added is, an open circuit occurs and makes all bulbs turn off.
<h3>What is a closed circuit?</h3>
A closed circuit is a type of circuit connection in which the wire connection is complete and current flow occurs, turning the light bulbs on in the process.
<h3>What is an open circuit?</h3>
An open circuit is a type of circuit connection in which the wire connection is incomplete and current cannot flow, turning off the light bulbs.
Thus, the circuit change when the wire is added is, an open circuit occurs and makes all bulbs turn off.
Learn more about open circuit here: brainly.com/question/20351910
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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:
The box of rocks will have depression which can be seen without touching the box.
Explanation:
The density of rocks is very large as compared with napkins. So, the weight of the rocks will be much more greater than that of napkins.
As both boxes have same volume the heavier box will show depression on the lower surface as compared to the lighter box. So, the box of rocks will have depression which can be seen without touching the box.