Ix amy SPH301 Gi ALTERNATE PON Lesson 06 Using the formula for power: Energy P = At Substitute in the formula for Work. You will notice that power can be expressed as a force multiplied by another quantity (look at the remaining terms to determine that quantity). A. Write the alternate formula for power: EXAMPLE 1 If a car engine does 25,000 kJ of work over 12 s to climb a hill, calculate the average power of the engine. (2.1 x 106 W) EXAMPLE 2 A 90 kW motor exerts an average force of 4.0 kN to move a speedboat at a constant speed through the water. How fast, in km/h, is the boat moving? (81 km/h) EXAMPLE 3 A snow tubing lift pulls riders up a 120 m long hill at a constant speed. The hill makes an angle of 220 to the horizontal and there is 145 N of friction between the tubes and the snow. The rider is 55 kg. and it takes 30.0 s to get up the hill. Sketch a labeled diagram: a) How much work does friction do? b) What will be the gain in the rider's gravitational potential energy? c) How much work will the lift need to do?The Wave Equation Check Your Understanding Questions 1-6 from https://www.physicsclassroom.com/Class/waves/u1012e.cfm Frequency, Time Period and the Universal Wave Equation 24. A tuning fork's tines vibrate 250 times in 2.0 s. Find 30. Find the period and velocity for the following a) the frequency of vibration. frequencies if the wavelength is 0.50 m: a) 0.30 Hz b) 400 s- b) the period of vibration. c) 30 cycles/s d) 5.0 kHz 25. There are six classes in one day. If all the e) 102.1 MHz classes take 6.5 hours each day, find the 31. Find the frequency and velocity given that the a) frequency of the classes occurring each day: wavelength is 75 em for the following periods. b) period of the classes. a) 0.020 s b) 15.0 ms 26. The frequency of a note is 440 Hz. Find the c) 2.0 min d) 0.6 h wavelength of the sound given that the speed 32. You are shouting in a monotone voice with a of sound is frequency of 440 Hz Your friend is 300 m a) 332 m/s. b) 350 m/s. c) 1225 km/h. away. If the speed of sound is 344 m/s, how 27. The frequency of a tuning fork is 1000 Hz. IF many wavelengths occur between you and the wavelength is 35 cm, find the speed of your friend? sound in a) m/s. b) km/h. 28. Gravity waves are still being searched for by astrophysicists. These waves travel at the 24) a) 1.3 x102 Hz b) 0.0080 s speed of light (c = 3.0 x 10 m/s). If the 25 ) a) 0.0026 Hz expected frequency is about 1600 Hz and the b) 3.9x103 s size of a football field is 250 m. how many 26) a) 0.755 m football fields long is the wavelength of a b) 0.795 m gravity wave? c) 0.773 m 27) a) 3.5x102 m/s 29. If 2/4 is 0.85 m and the frequency is 125 Hz, b) 1.3x103 km/h Find: 28) 7.5 x102 fields 29) a) 3.4 m a) The wavelength b) 0.0080 s b) The period of the wave c) 4.3x102 m/s c) The velocity of the wave 30 a) 3.3 s, 0.15 m/s b) 4.0x102 s, 2.0x102 m/s c) 0.033 s, 15 m/s d) 0.00020 s, 2.5x102 m/s e) 9.794x10-9 s, 5.1x10' m/s 31) a) 50 Hz, 38 m/s b) 66.7 Hz, 50 m/s c) 0.0083 Hz, 0.0063 m/s d) .0005 Hz, 3x10 4 m/s 32) 384 waves C