A deadlift is a weightlifting exercise in which a weighted bar is raised straight up from the ground, pulled to the height of the weight lifter's hips, and then placed back on the ground. The world record for deadlifting is 500kg.
(a) How much work did the world record lifter do in raising the bar up to a height of 95 cm?
(b) How much work did he do while lowering the bar back to the ground?

Next a skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 15 with the horizontal. the rope moves parallel to the slope with a constant speed of 0.69 m/s. the force of the rope does 800 3 of work on the skier as the skier moves a distance of 8.4 m up the incline. (a) if the rope moved with a constant speed of 2.2 m/s how much work would the force of the rope do on the skier as the skler moved a distance of 8.4 m up the incline? at what rate is the force of the rope doing work on the skier when the rope moves with a speed of (b) 0.69 m/s and (c) 2.2 m/s?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

Which of the following are appropriate acceleration units?