This energy transformation diagram represents the
energy of a boulder, initially positioned on top of a
mountain. as it falls, its original gravitational potential
energy is converted to kinetic energy and air friction,
how much of the energy is kinetic?

Gotta have a picture ^^

Distance covered, s = 8ft - 4ft = 4 ftinitial velocity, u = 34 ft/sthe acrobat is moving upwards and therefore, a = -g = -9.81 m/s^2 = 32.19 ft/s^2applying equation of motion; s = ut -1/2gt^2then,4 = 34t -1/2*32.19t^24 = 34t - 16.095t^2rearranging; -16.095t^2 + 34t - 4 = 0solving the quadratic equation; t = {-34 +/- sqrt [34^2 - 4(-16.)]}/2(-16.095) = 1.06 +/- 0.93 = 0.13 or 1.99the acrobat will take 0.13 seconds to be at 8 ft above the ground. additionally, once at the maximum height, the acrobat will move down and be at the same spot (that is height) after 1.99 seconds moving down.

Despite their crazy structure, human bones are surprisingly good!

Because there is no air in the jar, the vibrations can not travel through the air and create sound.  (that's why there is no sound in space, there is no air)