Answer:
1) Proportion of light bulbs lasting less than 1380 hours.
P(X<1380) = 0.2317(4dp)
2)The longest lasting 5% of light bulbs last 1736.7 hours or more
3) The middle 85% of light bulbs last between 1274.1 and 1705.9 hours
4) Proportion of light bulbs lasting between 1310 hours and 1680 hours is 0.7823 (4 dp)
5) Proportion of light bulbs lasting more than 1680 hours is 0.1026(4dp)
6) The shortest lasting 10% of light bulbs last 1297.8 hours.
Explanation:
The calculations are handwritten and attached as files to this solution. Check the files below for all the workings
The wavelength of the third resonance of the closed organ pipe is equal to the ratio between the speed of sound and the frequency of the 3rd harmonic:
The relationship between length of a closed pipe and wavelength of the standing waves inside is:
where n is the number of the harmonic. In this case, n=3, so the length of the pipe is
Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat
cliff is away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know
therefore frequency of the echo slightly decreased.