The anode of the x rays tube has to be cooled..give the reason​

What is hidden during a lunar eclipse? isn't the moon hidden?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk,in meters?

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?