Specific heat refers to the amount of heat required to change 1 gram of a substance by degree(s) celsius

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 ?

The graph describes the motion of an object. the object moves with from a to b. it from b to c. it moves with from c to d.

Which of these is not a possible type of energy transformation? a. electrical energy into light energy b. sound energy into nuclear energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy