Circuit breaker is a device that is designed to open an overloaded circuit and prevent overheating. The correct option in regards to the given question is option "a". The main purpose of the circuit breaker is to disconnect the defective switch from the circuit as soon as any problem arises. This helps in preventing any kind of major accident. Overheating can result in a big accident and the circuit breaker is the device that senses the overheating and disconnects the switch before any major incident. It is an automated system that acts as a protective devise.
Nuclear energy was not developed. It has existed for as long as time has existed, that is, since the big bang.
The thing that was developed was humans' ability to USE nuclear energy, to do what we want it to do, when we want it to do it.
The reason this was first developed was to bomb the holy beans out of Japan, in order to win World War II.
Today (2020), nine of the world's nations are known to have 14,285 nuclear bombs in storage, for the same general purpose. Seven of these nations are storing 1,170 of these bombs (about 8 percent), and the USA and Russia have all the rest ... 13,035 nuclear bombs.
All nine of these nations promise that they have no plan to use their bombs, they don't want to use them, it would be wrong and terrible to use them, and they will never be the first to use them, but they need to modernize their bombs so that theirs are better than anybody else's bombs, and they need to keep their bombs for as long as anybody else has any, and then maybe a little longer, just in case.
In the years after the ability to bomb the holy beans out of other people was developed, and enough equipment was built to do it 14 thousand times, the ability to use nuclear energy for other purposes was also developed. It's used now to generate electrical energy, and to do several jobs in Medical science.
Answer: it is due to friction.
Explanation: if you were to push an object that is at rest, there is static friction that you would first need to overcome. An example would be pushing a car as it is in neutral. Pushing it takes more force and work to overcome that friction.
But once it overcomes static, it will then turn to kinetic friction. Once the car starts to move, you notice that it is easier to push. This is due to the fact that kinetic friction would equal normal force times the constant while the static friction is greater than or equal to the normal force times the constant.
Hope this helps!!!
