A firefighter a distance d from a burning building directs a stream of water from a fire hose at angle θi above the horizontal as in the figure. If the initial speed of the stream is vi, at what height h does the water strike the building? (Use any variable or symbol stated above along with the following as necessary: g.)
IE/R. In general the wire resistance is much less than the other circuit resistances. If you want to reduce I, increase the resistance, R.
The best place is the highest place. If a fire starts, smoke will hit the roof and spread along it. It will have no trouble spreading past doorways (unless the door is closed) even if the top of the door is lower than the ceiling. Obvious places to put them are near the kitchen and if your house has two floors, immediately at the top of the stairs (so smoke from below will hit it if it goes up the stairs). Smoke alarms are very cheap so it's sensible to buy two or three. If you put one IN the kitchen it will go off when you're cooking, but if you put one in the hall outside it or away from the oven/hob then you might be alright, otherwise buy a heat detecting one rather than a smoke detecting one. If you have children it's a good idea to make sure they know what to do if they wake up with a room full of smoke, and also if they don't but hear the fire alarm going off. Remember to check the doorhandles before you walk into a room if the smoke alarm is going off by lightly touching it with the back of your hand. If it's hot to the touch, do not open the door. Stay low, and plan how to get out of your house. If you are trapped, keep the door closed and put a blanket at the bottom of the door. Call the emergency services and lie low on the floor. Plan the best ways out of your house and place your smoke alarms accordingly.
