How much is the relative velocity of two car moving along a straight path with same velocity

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

Amagnetic field applies forces on: a)static chargesb)moving chargesc)water flow

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?