[填空题]
A 920-kg sports car collides into the;(d,bbo ngqi xf p6o49 rear //3ko m,j zgo9kzzky:end of a 2300-kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.8 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.80, calculates the skz9okg3 okyj,z:/ m /zpeed of the sports car at impact. What was that speed?(Let A represent the sports car, and B represent the SUV) $\approx$ m/s
