A cup of hot coffee at a temperature of 80 C is left out on a table top. The surrounding air has a temperature of 25 C (room temperature). After one hour on the table top: * A. The coffee will absorb the heat from the air and become hotter
b. the heat will flow from the coffee to the surrounding air.
C. the coffee will freeze and become solid.

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

If the speed of a particle triples ,by what factor does its kinetic energy increase?

The air that we breath is made mostly of which gaseous molecule