Which Sl units are combined to describe energy? A. Kilograms and m/s2
B. Kilograms and joules
C. Kilograms and m/s2
D. Kilograms and meters

kilograms and m²/s²

Explanation:

The SI units combined to describe energy is kilograms and m²/s² ;

  Energy can be derived from;

Potential energy  = mgh

   Units               = kg x m/s² x m

                          = kg m²/s²

Even if we use kinetic energy, we still get kg m²/s²

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation:

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be