[填空题]
Two children are playing on two trampolines. The first child can hsw(b 83xu)xz bounce up one-.gk-t 0m4gbvg and-a-half times higher than the se t4km0-g vb.ggcond child. The initial speed up of the second child is $5.0 m/s $.
(a) Find the maximum height the second child reaches. $\approx$ m(retain one decimal places)
(b) What is the initial speed of the first child? $\approx$ m/s(retain one decimal places)
(c) How long was the first child in the air? s