The position time graph for an object moving with constant acceleration starts off with a positive slope. At later times the slope becomes negative. Is the initial velocity of this object positive, negative, or zero?

Is the acceleration positive, negative or zero?

a displacement distance is size of displ

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.

snell's law

refractve index = sin incidence / sin refraction