The parking brake on a 1000 kg cadillac has failed, and it is rolling slowly, at 1 mph , toward a group of small children. seeing the situation, you realize you have just enough time to drive your 2000 kg volkswagen head-on into the cadillac and save the children.

Um of momenta = 0( Since both the cars stop) 
Let m1 be the mass of the cadillac and m2 be the mass of the volkswagen. 
then, v1=speed of cadillac and v2=speed of volkswagen. 
Therefore, (m1)*(v1) + (m2)*(v2) = 0 
Substituting, 
(1000*4) + (2000*v2) = 0 
4000 = - 2000 v2 
Therefore, v2= - 2 m/s. 

Definitely the indoraptor

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling