A physics professor demonstrates the Doppler effect by tying a 900 Hz sound generator to a 1.0- m -long rope and whirling it around her head in a horizontal circle at 100 rpm . 1. What is the difference between the highest frequency heard by a student in the classroom and the initial frequency of the sound generator?
2. What is the difference between the lowest frequency heard by a student in the classroom and the initial frequency of the sound generator?

Three different objects, all with different masses, are initially at rest at the bottom of a set of steps. each step is of uniform height . the mass of each object is a multiple of the base mass : object 1 has mass 4..00m , object 2 has mass 1..96m , and object 3 has mass . when the objects are at the bottom of the steps, define the total gravitational potential energy of the three-object system to be zero. if the objects are then relocated as shown, what is the new total potential energy of the system? each answer requires the numerical coefficient to an algebraic expression. each algebraic expression is given using some combination of the variables , , and , where is the acceleration due to gravity. enter only the numerical coefficient. (example: if the answer is 1..23mgd , just enter 1.23)