The seatbelts purpose was to keep the egg secure during the impact. In order to do this, Newton’s first law had to be taken into consideration, objects at rest, stay at rest; object in motion, stay in motion… unless acted upon by an unbalanced force. Because the egg would have kept going until acted on by an unbalanced force, we suspended it with rubber bands so that the unbalanced force to stop it would not be the ground but it would be the pressure applied by the rubber band. This also Apply to Newton's third law which states that every action has an opposite and equal reaction. when the carrier hits the ground the ground also pushes back on the carrier which would crack the egg if it were not suspended by rubber bands. Since it is suspended,the
