The <span>flow of how a cold pack works on a sprained ankle is based on the second law of thermodynamics which states that energy will flow from a higher to a lower temperature. So your body heat will flow to the cold pack in which you will feel the coldness of the pack.</span>
Slow-twitch<span> muscles help enable long-endurance feats such as distance running.
</span>fast-twitch<span> muscles fatigue </span>faster<span> but are used in powerful bursts of movements like sprinting.</span>
(6) first choice: the frequency appears higher and wavelength is shorter.
The car approaches a stationary observer and so the sound will appear to have shorter wavelength. This creates an effect of its siren to sound with higher frequency than it would do if both were stationary.
(7) The Doppler formula for frequency in the case of a stationary observer and source approaching it is as follows:

The wavelength is then

The third choice "0.80m; 431Hz" is correct
The answer is D.
Hope this helps and have a good day :D