Wave Equation calculations

1. A water wave has a frequency of 2 Hz and a wavelength of 10cm (trap). Calculate its velocity. 0.2 m/s

 

2. A certain metal sound of wavelength 4.3 m has a frequency of 1500 Hz. Calculate its velocity. 6450 m/s

 

3. The frequency of a radio station is 1 200 kHz. What wavelength does it transmit on? 250m

 

4. A certain note has a wavelength of 15cm. Calculate its frequency.2266.7 Hz

 

5. A ray of light has a wavelength of 0.000 000 006m. Calculate its frequency.    5 x10¹⁴ Hz

 

6. A radio station broadcasts on 1760m. Calculate its frequency. 170 kHz

 

7. The lowest frequency that the human ear can detect is 20Hz (approx). 1.7m The highest is 20 kHz 1.7 mm(trap). Work out the wavelengths of these frequencies.

 

8. The distance between successive crests of a sea wave is 4 m. They pass a stationary observer every 20 seconds. What is the velocity of the wave?

 

9. Ripples pass along a pond. The distance between successive crests is 6 cm. The waves travel 0.5 m in 3 s. v=x/t =0.5/3 = 0.16m/s What is the wavelength in m 0.06m and the frequency? 2.67 Hz

 

10. Ripples pass along a pond at 0.3 m/s. What is their wavelength if the frequency is 6 Hz? 0.05m

 

Two people stand some distance apart on a railway line on a still day. One person puts her ear to the rail. The other hits the rail once with a sledge hammer. The listener hears two bangs, 1 second apart. Explain.

If the speed of sound in steel is 5500m/s calculate the distance between the listener and the hammerer. 362 m

The Wave Equation

wave machines

Waves

Efficiency of an Inclined Plane

Power

. 

                                                            POWER

                                            Power = Work = Energy Transferred       

                                                            Time            Time

                  

                                                Time must be in seconds

1.         A light bulb converts 500 J of electrical energy into heat and light in

            5 seconds. What is its power rating?

2.         An electric kettle converts 210,000 J of electrical energy into heat energy in 1       minute. Calculate its power rating?

3.         A person of weight 500 N climbs a 5m flight of stairs in 100 s. Calculate the          power produced.

4.         A car of mass 500 kg is driven up an incline of vertical height 5m in 5s.      Calculate the power output of the engine.

            [Gravitational field strength = 10 N/kg]

5.         Calculate the energy transferred by a 300 W TV in 25 seconds.

6.         Calculate the energy transferred by a 0.0002 W calculator in 5 minutes.

7.         A hoist motor develops 500 W. It does 1000 J of work in lifting a mass.        How long does it take to lift the mass?

8.         A car develops 44 kW. It does 1980 kJ of work in travelling a certain

            distance. How long does this take?