题目

One spring morning many years ago, I was on southeastern Alaska’s Kupreanof Island when I saw a huge wolf caught in a trap. From her appearance, I realized it was a mother wolf and that somewhere hungry pups (小崽) were waiting for her. I guessed she had been trapped only a few days. So her pups were probably still alive, hungry, surely no more than a few miles away. But I thought if I released the wolf, she would tear me to pieces.So I decided to search for her pups instead. Following some footprints, I finally found four tiny pups. One by one, I placed them in a bag and headed back. When某商场扶梯的高度是5m，扶梯长是8m，小明体重为600N．扶梯把小明从三楼匀速送上四楼的过程中，小明的动能__(填变化情况)；扶梯对小明做功____J，如果要知道扶梯对小明做功的功率，还应该测量的物理量是____．