2. It is weighin time for the local under85kg rugby tea m. The bathroom scale used to assess eligibility can be described by Hooke's law and is depressed 0.75 cm by its maximum load of 120 kg. {a} What is the spring's effective spring constant? {b} A player stands on the scales and depresses it by 0.48 cm. Is be eligible to play on this unden85 kg team? 7. What is the period of 60.0 Hz electrical power? 15. A0.500kg mass suspended from a spring oscillates with a period of 1.50 s. How much mass must be added to the object to change the period to 2.00 s? 24. What is the period of a 1.00mlong pendulum? 36. Engineering Application Near the top of the Citigroup Center building in New York City, there is an object with mass of 4.00 x 1045 kg on springs that have adjustable force constants. Its function is to dampen windclriven oscillations of the building by oscillating at the same frequency as the building is being driventhe driving force is transferred to the object, which oscillates instead of the entire building. {a} What effective force constant should the springs have to make the object oscillate with a period of 2.00 s? {b} What energy is stored in the springs for a 2.00m displacement from equilibrium? 37. {a}What is the maximum velocity of an 85.0kg person bouncing on a bathroom scale having a force constant of 1.50 x 1046 film, if the amplitude of the bounce is 0.200 cm? {bJWhat is the maximum energy stored in the spring? 48. Waves on a swimming pool propagate at 0.750 mfs. You splash the water at one end ofthe pool and observe the wave go to the opposite end, reect, and return in 30.0 s. How fa r away is the other end of the pool? 50. How many times a minute does a boat bob up and down on ocean waves that have a wavelength of 40.0 m and a propagation speed of 5.00 mfs? 62. Three adjacent keys on a piano (F, Fsharp, and G] are struck simultaneously, producing frequencies of 349, 370, and 392 Hz. What beat frequencies are produced by this discordant combination? 71. Medical Application (a) What is the intensity in meAZ of a laser beam used to burn away cancerous tissue that, when 90.0% absorbed, puts 500] of energy into a circular spot 2.00 mm in diameter in 4.00 s? [b]: Discuss how this intensity compares to the average intensity of sunlight {about 700 mei'gand the implications that would have if the laser beam entered your eye. Note how the amount of damage depends on the time duration of the exposure