The speed of a train is decreased in a uniform rate from 96km/h to 48km/h through a distance of 800 m due to using the brake .calculate the distance covered by the train from the moment of using the brake till it stop ,if it was moving with the same acceleration .

Anybody wanna ? (picture included? )

It is really hard for me right know

On a mild saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23degreesc. at noon the furnace is turned off, and the people go home. the temperature outside is a constant 16degreesc for the rest of the afternoon. if the time constant for the building is 3 hr, when will the temperature inside the building reach 18degreesc? if some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18degreesc?