2:54AM Sat Mar 9 (XY} Qe 2ag HCHW Ch 1 (14).pdf @] . 4 4 HELP: See picture and Vsypere = ST 10.8. a. A physics formula has the form v = /1f where v is speed in units of %and fis frequency in units of 1/second. For this formula to be dimensionally consistent, what are the units of 1? b. A physics formula has the form I = edAT* where [ is intensity in units of Watts/meter?, e is unitless, A is area in units of meter? and T is temperature in units of Kelvin. For this formula to be dimensionally consistent what are the units of ? ANS: Watt/m* : Kelvin* 11.9. We will learn in Chapter 6 that the force F necessary to keep an object moving in a circle is directly proportional to the square of the object's speed, v2. a. As v increases what happens to v? (does it increase or decrease)? What then happens to F (i.e., does it increase or decrease)? Write an equation that relates the two variables F, v2 using an unknown constant k. . A car moving around a circular track at a speed of 20 mile/hour requires the frictional force between its tires and the ground to be 500 pounds. What is the value and units of the proportionality constant. What is the equation that relates the two variables F, v? using an unknown constant k. d. Ifacar'sspeedis 15 mile/hour whatis the value of the force? 12.9.E. Two variables may be directly proportional or inversely proportional. To say that y is inversely proportional to x means that as one variable goes up the other variable goes down and vice versa. y . . . . . 1 y is inversely proportional to x is symbolized y S This means there is some constant k so that the equation relating y to x is given by 0 X We will learn in Chapter 14 that brightness of light called its intensity I is inversely proportional to the square of the distance 2 from the light source. a. As 7 increases what happens to 72 (does it increase or decrease)? What then happens to I (i.e., does itincrease or decrease)? Write an equation that relates the two variables I, 72 using an unknown constant k. c. The intensity from a light source is 50 Watts/meter? when observed from 2 meters away. What is the value and also the units of the proportionality constant. What is the equation that relates the two variables I, 2 using your value for k. Q Notifications SRS Bt PN