Simple Nature - Light and Matter

Problem 45the 0.4-gram masses would have been about 3 × 10 −19 N, oscillatingwith a period of 24 hours due to the rotation of the earth. (We ignorethe inertia of the arms, whose total mass was only about 25%of the total mass of the rotating assembly.)(a) Find the amplitude of the resulting oscillations, and determinethe angle to which they would have corresponded, given that theradius of the balance arms was 10 cm. ⊲ Answer, p. 930(b) Show that even if their estimate of Q was wildly wrong, itwouldn’t have affected this result.44 A firework shoots up into the air, and just before it explodesit has a certain momentum and kinetic energy. What can you sayabout the momenta and kinetic energies of the pieces immediatelyafter the explosion? [Based on a problem from PSSC Physics.]⊲ Solution, p. 93445 The figure shows a view from above of a collision aboutto happen between two air hockey pucks sliding without friction.They have the same speed, v i , before the collision, but the big puckis 2.3 times more massive than the small one. Their sides havesticky stuff on them, so when they collide, they will stick together.At what angle will they emerge from the collision? In addition togiving a numerical answer, please indicate by drawing on the figurehow your angle is defined. ⊲ Solution, p. 93446 A learjet traveling due east at 300 mi/hr collides with ajumbo jet which was heading southwest at 150 mi/hr. The jumbojet’s mass is five times greater than that of the learjet. When theycollide, the learjet sticks into the fuselage of the jumbo jet, and theyfall to earth together. Their engines stop functioning immediatelyafter the collision. On a map, what will be the direction from thelocation of the collision to the place where the wreckage hits the√ground? (Give an angle.)47 (a) A ball is thrown straight up with velocity v. Find an√equation for the height to which it rises.(b) Generalize your equation for a ball thrown at an angle θ abovehorizontal, in which case its initial velocity components are v x =√v cos θ and v y = v sin θ.48 At the 2010 Salinas Lettuce Festival Parade, the LettuceQueen drops her bouquet while riding on a float moving toward theright. Sketch the shape of its trajectory in her frame of reference,and compare with the shape seen by one of her admirers standingon the sidewalk.49 Two daredevils, Wendy and Bill, go over Niagara Falls.Wendy sits in an inner tube, and lets the 30 km/hr velocity of theriver throw her out horizontally over the falls. Bill paddles a kayak,adding an extra 10 km/hr to his velocity. They go over the edge226 Chapter 3 Conservation of Momentum