Aphysics professor that doesn’t get easily embarrassed stands at the center of a frictionless turntable with arms outstretched and a 5.0-kg dumbbell in each hand. he is set rotating about the vertical axis, making one revolution in 2.0s. find his angular velocity if he pulls the dumbbells to his stomach. his moment of inertia (without the dumbbells) is 3.0 kg*m^2 with arms outstretched and 2.2 kg*m^2 with his hands at his stomach. the dumbbells are 1.0 m from the axis initially and 0.20 m at the end. how about kinetic energy before and after? explain from where this energy (if any) came from?

Zeros that follow non-zeros numbers and are also to the right of a decimal point are significant

Part f - example: finding two forces (part i) two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?