2 flies, Pablo and Pedro, stand on a solid rotating disc of radius 9.5 cm, initially at rest. pablo is on the outer edge of the disk and pedro is a third of the way from the center to the edge. the disc begins rotating with a constant angular acceleration, reaching 50 rpm in 5 seconds. after 7 seconds, the discs angular speed becomes constant. the flies have a mass of 0.015 g each and their coefficient of friction with the disc is 0.250. how many times did pablo rotate until he could no longer hold on to the disk? give your answer in revolutions and as a number between 0 and 2 pi.

In which of the following cases is work being done on an object? question 2 options: pulling a trailer up a hill carrying a box down a corridor suspending a heavy weight with a strong chain pushing against a locked door

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10