Answer:
water at 55°C
Explanation:
Sound is a mechanical wave, which travels through a medium by the vibrations of the particles in the medium, which collide with each other, allowing the sound wave to propagate through the medium.
Based on this explanation, we can understand two facts:
1) sound waves travel faster in solids than in liquids. This is because the particles inside a solid are much closer together than in a liquid, so the wave can be transferred faster because there are more collisions between the particles of the solid
2) The speed of a sound wave increases as the temperature increases. This is because at higher temperatures, particles move faster, so the wave can be transmitted faster.
Therefore, #1 tells us that sound travels slower in water than in ice, while #2 tells us that sound travels slower at 55°C than at 75°C . Therefore, sound travels slowest in water at 55°C .