Which type of platform lift has the lifter starting by holding the bar off the ground with straight arms then hinging forward until the bar lowers slightly past their knees and finally driving their hips forward until standing at the original
position?

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.