The diesel engine has no ignition system. (C)
It depends on the compression of the fuel/air mixture to ignite the mixture.
This may be a big part of the reason that Diesel engines always
sound to me as if they are falling apart.
The answer is pluto. just look it up
I could be wrong but I believe it’s 1/2
A)Ep'=mgh=mgl(1-cosa).At the bottom of the swing Ep=0(reference level),so the potential energy as the child is just released is bigger than the potential energy at the bottom of the swing.;B)The speed of the child at the bottom of the swing-->v=√(2gh)=√[2gl(1-cosa)];C)I don't think that the tension does any work.