Two physical characteristics of a wave are amplitude and wavelength. The amplitude of a wave is the height of a wave as measured from the highest point on the wave (peak or crest) to the lowest point on the wave (trough). Wavelength refers to the length of a wave from one peak to the next.
Explanation:
As you can see in the picture, we want the swimmer to go on a straight line, so the speed of the water must be equal to the speed of the swimmer along the x-axis. We also know the value of v, so we can calculate the of the cosine of the angle (alpha) between Vx and V. Thanks to the fundamental relation of gioniometry (cos^2(x) + sin^2(x) = 1) we can find the sine of alpha and calculate Vy. With Vy we can calculate the time that the swimmer will use for reaching the dock: s = Vy * t => t = s/(Vy).
I'll let you do all the calculations, you just have to plug in values.
Answer: 26.84 m/s
Explanation:
Given
Original frequency of the horn 
Apparent frequency 
Speed of sound is 
Doppler frequency is

Where,

Insert values
![\Rightarrow 246=228\left[\dfrac{340+v_o}{340-0}\right]\\\\\Rightarrow 366.84=340+v_o\\\Rightarrow v_o=26.8\ m/s](https://tex.z-dn.net/?f=%5CRightarrow%20246%3D228%5Cleft%5B%5Cdfrac%7B340%2Bv_o%7D%7B340-0%7D%5Cright%5D%5C%5C%5C%5C%5CRightarrow%20366.84%3D340%2Bv_o%5C%5C%5CRightarrow%20v_o%3D26.8%5C%20m%2Fs)
Thus, the speed of the car is 
The tension in the upper rope is determined as 50.53 N.
<h3>Tension in the upper rope</h3>
The tension in the upper rope is calculated as follows;
T(u) = T(d)+ mg
where;
- T(u) is tension in upper rope
- T(d) is tension in lower rope
T(u) = 12.8 N + 3.85(9.8)
T(u) = 50.53 N
Thus, the tension in the upper rope is determined as 50.53 N.
Learn more about tension here: brainly.com/question/918617
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