Gizmo Warm-up: Lifting a piano A pulley is a simple machine that is used to lift heavy objects. A pulley is a wheel with a groove for a rope. Pulling down on one end of the rope causes the other end to pull up. In the Object to lift menu choose Piano. What is the weight of the piano

It really doesn't matter for any of the questions that you've listed.

Work is reduced while time is decreased

Answertechnician (a) is correct;

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.