8. Calculate the relativity factor for two observers whose relative velocity is 0.43c. 9. An observer stands next to a lightning rod in an inertial reference frame at rest with respect to a barn's weather vane 9.50 x 108 meters away. The observer sees lightning strike the vane 2.00 seconds before it strikes the lightning rod. Find the proper time between the evenis . 9.50 x 10# m 10. An observer in another reference frame measures the time interval between two events that occur at the same place. measures the rest mass of an object, and measures the distance between two fixed points in his reference frame. We will make the same measurements in our reference frame that is moving with a constant velocity with respect to the observer's reference frame. An observer in a spaceship moving at 0.65c with respect to the earth made proper measurements of time, mass, and length parallel to the relative velocity. He measured 3 hours. 32 kilograms, and 0.18 m. What measurements would we get for (a) Time (b) Mass (c) Length parallel to the relative velocity Physics by Saxon1. The first sound had an intensity of 1.63 x 10" watt per square meter. and the second sound had an intensity of 4.18 x 10"- watt per square meter. By how many decibels was the second sound greater than the first sound? 2. The length of a half-wavelength dipole antenna is 3.4 meters. For what fundamental frequency was this antenna designed? 3. In the following diagram, let's use a gear with 30 evenly spaced teeth and a distance D of 12.5 kilometers. The speed of rotation is adjusted so that an outgoing pulse is blocked by the next tooth when it comes back. We estimate the angular speed of the gear to be 180 revolutions per second. What speed of light do we get? -D Light source Toothed Mirror wheel 4. Water is hard to compress as its bulk modulus is 2.0 x 10 pascals. If a volume of water is subjected to a pressure increase of 150 pascals and its initial volume is 480 cubic meters, (a) What will be the fractional decrease in the volume? (b) What would be the change in volume? 5. Tem holds a flashlight whose rays travel at 3.00 x 10 m/s. Michael's truck is traveling in the same direction at 2.18 x 10 m/s. When he looks at the rays from Terri's flashlight, how fast does he think the rays are moving? 2.18 x 108 m. s-1 3.00 x 108 mis- 6. In the reference frame of observer A, the 4.60-kg mass is sliding in the positive x direction at 3.00 m/s. Observer B is moving toward observer A with a relative velocity of 7.00 m/s. (a) What kinetic energy does observer A calculate for the mass? (b) What kinetic energy does observer B calculate for the mass? (c) Which observer is correct? 3.00 m S 7.00- 4.60 kg B