Answer:
16m/s
Explanation:



Therefore, the speed after 8 seconds is 16m/s
Heidhebd bdjdishrhr bdjjdhdhrhr heheheh hdudjdhhf hdjdhdhf
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.
Answer: Magnetizim
Explanation: Magnetic Atoms collide creating magnetizim