F4 物理 十點plz

由於運動員以恆速滑動，故他的動能沒有增加。
運動員以水平方向滑動，因此他的勢能也沒有增加。

公式W=Fd（作功 = 力 x 位移）是用來計算繩子作了多少功。如果滑水橇和斜台之間存在摩擦力，而滑水員的速率依然不變，繩子所作的功便全都用來對這種抗摩擦力，作功的結果便是在滑水橇和斜台之間產生了熱能。如果它們之間沒有摩擦力，繩子便沒有作功。

If you refer to the "energy"(能量) of the skater, but not "kinetic energy"(動能), I don't think your answer of 0 J is right.

The skater is moving up on the sloped platform at a constant speed of 10 m/s, clearly he gains potential energy from his motion though his kinetic energy remains unchanged.