Which of the following statements most accurately differentiates potential and kinetic (a)kinetic energy is a form of mechanic energy, while gravitational potential is not.(b.)any object that has motion has kinetic energy, while any object not in motion but with the potential to do work has potential energy.(c)gravitational potential energy is a form of mechanical energy, while kinetic energy is not.(d)any object that has motion has potential energy, while any object not in motion but with the potential to do work has kinetic energy

Let f(x) = x4- 8x2 . find the relativeextrema of this function using the second derivative test.

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.