A cup filled with water is put on a slope. The slope makes a angle of 45 degrees with the ground. The cup with water is sliding down with a constant velocity. When the cup is sliding down, the water surface of the water inside the cup is parellel to the ground or making a angle to the ground?
I am really confused with the question, plz help.
更新1:
Yes, that's my answer too. Because according to the principle of relativity, object at rest is indistinguishable from object moving with constant velocity. However....the exercise said water surface is parallel to the slope= =
更新2:
Thank you,physics8801,I understand now.