Answer:
f3 = 102 Hz
Explanation:
To find the frequency of the sound produced by the pipe you use the following formula:

n: number of the harmonic = 3
vs: speed of sound = 340 m/s
L: length of the pipe = 2.5 m
You replace the values of n, L and vs in order to calculate the frequency:

hence, the frequency of the third overtone is 102 Hz
Answer:d
Explanation:
Spring is compressed to a distance of x from its equilibrium position
Work done by block on the spring is equal to change in elastic potential energy
i.e. Work done by block 
therefore spring will also done an equal opposite amount of work on the block in the absence of external force
Thus work done by spring on the block 
Thus option d is correct

P=25x10^6 andF=750.So plug in everything to solve for A. which is 3x10^-5m^2 OR 0.3mm^2
The answer should be:
<span>To prevent collisions and violations at intersections that have traffic signals, use the d</span>elayed acceleration technique<span> to ensure the intersection is clear before you enter it.
Delayed acceleration technique refers to w</span><span>aiting to go through an intersection until you have a chance to scan for other vehicles.</span>