Principles<span> of </span>arc welding<span>. </span>Arc welding<span> is a </span>welding<span> process, in which heat is generated by an </span>electric arc<span> struck between an electrode and the work piece. </span>Electric arc<span> is luminous</span>electrical<span> discharge between two electrodes through ionized gas.</span>
Answer:
9.22 s
Explanation:
One-quarter of a turn away is 1/4 of 2π, or π/2 which is approximately 1.57 rad
Let t (seconds) be the time it takes for the child to catch up with the horse. We would have the following equation of motion for the child and the horse:
For the child: 
For the horse: 
For the child to catch up with the horse, they must cover the same angular distance within the same time t:



t = 25.05 or t = 9.22
Since we are looking for the shortest time we will pick t = 9.22 s
In my opinion the answer is B. Variation
I think A but I dont really know
The centripetal force needed to keep earth in orbit is gravity.