Suppose that you are going to program a computer to carry out an iterative calculation of motion involving nonconstant forces. Which of the following calculations should be done before starting the repetitive "loop" calculations? Specify the initial (vector) momentum of each object. Calculate the (vector) forces acting on the objects. Specify an appropriate value for the time step. Update the (vector) position of each object. Specify the mass of each object. Define constants such as G. Update the (vector) momentum of each object. Specify the initial (vector) position of each object.

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

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.

Match each type of lever with the correct diagram. 1. first-class 2. third-class 3. second-class