题目

阅读理解 Mr Smith made many tests (作试验) with different animals and the monkey was the cleverest of all the animals. One day Mr Smith put a monkey in a room. He also put some small boxes in it. In one of the boxes there was some food. How long will it take the monkey to find the food? Mr Smith said to himself. Let me wait and see. He left the room and waited outside. Three minutes later, he put his eye to the keyhole (钥匙眼). What did he see? He saw the eye of the monkey. The monkey was on the other side of the door and looked at Mr Smith through the keyhole. 1. Mr S5．传送带上有一个物体M，重为2N，它与传送带一起以0.5m/s的速度在水平方向向右匀速运动，不计空气阻力．请在图中画出M的受力示意图．