Nuclear physics<span> is the study of the protons and neutrons at the centre of an atom and the interactions that hold them together in a space just a few femtometres (10-15 metres) across. It would be advantageous because we understand how atoms behave. Hope this answers the question.</span>
Explanation:
Given that,
Bill is riding his bicycle at 5 m/s eastward: and Carlos is driving his car at 15 m/s westward.
Taking eastward as positive direction, we have:
is the velocity of Bill with respect to Amy (which is stationary)
is the velocity of Carlos with respect to Amy.
Bill is moving 5 m/s eastward compared to Amy at rest, so the velocity of Bill's reference frame is

Therefore, Carlos velocity in Bill's reference frame will be

So, the magnitude is 20 m/s and the direction is westward (negative sign).
It is most likely vegetable oil