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The pitch decreases because the higher the speed away from the observer, the lower the frequency.
johnmulu answered the question on February 11, 2017 at 08:54
- A girl standing 600 m away from a cliff bangs two pieces of wood together and hears an echo 3.5 seconds later(Solved)
A girl standing 600 m away from a cliff bangs two pieces of wood together and hears an echo 3.5 seconds later. Determine the speed of sound in air at the place.
Date posted: February 11, 2017. Answers (1)
- An observer watching a fireworks display sees the light from an explosion and hears the sound 2 seconds later(Solved)
An observer watching a fireworks display sees the light from an explosion and hears the sound 2 seconds later. How far was the explosion from the observer
Date posted: February 11, 2017. Answers (1)
- A mine worker stands between two vertical cliffs 400 m from the nearest cliff. The cliffs are x distance apart(Solved)
A mine worker stands between two vertical cliffs 400 m from the nearest cliff. The cliffs are x distance apart. Every time he strikes the rock once, he hears two echoes; the first one after 2.5s, while the second follows 2s later. From this information, calculate:
i) The speed of the sound in air
ii) The value of x.
Date posted: February 11, 2017. Answers (1)
- A ship in an ocean sends out an ultra sound whose echo is received after 3 seconds. If the wavelength of the ultra sound in water is 7.5 cm(Solved)
A ship in an ocean sends out an ultra sound whose echo is received after 3 seconds. If the wavelength of the ultra sound in water is 7.5 cm, and the frequency of the transmitter is 20 kHz,determine the depth of the ocean.
Date posted: February 11, 2017. Answers (1)
- The wavelength of a radio wave is 1 km. Determine its frequency.(Solved)
The wavelength of a radio wave is 1 km. Determine its frequency.
(Take the speed of light as 3.0 X 108ms-1)
Date posted: February 11, 2017. Answers (1)
- State difference between mechanical and electromagnetic waves(Solved)
State difference between mechanical and electromagnetic waves.
Date posted: February 11, 2017. Answers (1)
- The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect(Solved)
The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect.
(Speed of sound in air = 330m/s)
Date posted: February 11, 2017. Answers (1)
- Water waves are observed as they pass a fixed point at a rate of 30 crests per minute. A particular wave crest takes 2s to travel between two fixed points 6m apart.(Solved)
Water waves are observed as they pass a fixed point at a rate of 30 crests per minute. A particular wave crest takes 2s to travel between two fixed points 6m apart.
Determine for the wave:
i) The frequency
ii) The wavelength
Date posted: February 11, 2017. Answers (1)
- Give one example of a transverse wave and one example of longitudinal wave(Solved)
Give one example of a transverse wave and one example of longitudinal wave
Date posted: February 11, 2017. Answers (1)
- Calculate the wavelength of the KBC FM radio wave transmitted at a frequency of 95.6 Mega Hertz(Solved)
Calculate the wavelength of the KBC FM radio wave transmitted at a frequency of 95.6 Mega Hertz.
Date posted: February 11, 2017. Answers (1)
- State two distinctions between the way sound waves and electromagnetic waves are transmitted(Solved)
State two distinctions between the way sound waves and electromagnetic waves are transmitted.
Date posted: February 11, 2017. Answers (1)
- What is the difference between longitudinal and transverse waves?(Solved)
What is the difference between longitudinal and transverse waves?
Date posted: February 11, 2017. Answers (1)
- A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm(Solved)
A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm. Determine the moon's gravitational strength. (Take gravitational field strength on earth as 10 Nkg-1)
Date posted: February 11, 2017. Answers (1)
- A light spiral extends by 4 mm when loaded with a weight W. The spring is connected in series with an identical spring(Solved)
A light spiral extends by 4 mm when loaded with a weight W. The spring is connected in series with an identical spring. The combination is loaded with the weight W. Determine the extension of the combination.
Date posted: February 11, 2017. Answers (1)
- An object of weight 20 N attached at the end of a spring causes an extension of 0.5 cm on the spring(Solved)
An object of weight 20 N attached at the end of a spring causes an extension of 0.5 cm on the spring.
a) Determine the spring constant of the spring
b) Determine the weight of an object that would cause an extension of 0.86 cm when attached at the end of the same spring
Date posted: February 11, 2017. Answers (1)
- State the SI unit of a spring constant(Solved)
State the SI unit of a spring constant.
Date posted: February 11, 2017. Answers (1)
- You are provided with two wires of same material and same thickness. Describe how would make two spiral springs of different springs constants(Solved)
You are provided with two wires of same material and same thickness. Describe how would make two spiral springs of different springs constants (assume that other apparatus to make springs are available)
Date posted: February 11, 2017. Answers (1)
- State Hooke's law(Solved)
State Hooke's law.
Date posted: February 11, 2017. Answers (1)
- A wire fixed at one end extends by 4mm when a load of 20N is suspended from the other end. Determine the load that would cause an extension of 1.5 mm on the wire(Solved)
A wire fixed at one end extends by 4mm when a load of 20N is suspended from the other end. Determine the load that would cause an extension of 1.5 mm on the wire. (Assume elastic limit is not exceeded)
Date posted: February 11, 2017. Answers (1)
- State two ways in which the strength of an electromagnet can be increased(Solved)
State two ways in which the strength of an electromagnet can be increased.
Date posted: February 11, 2017. Answers (1)