1. The problem statement, all variables and given/known data A 870 kg sports car collides into the rear end of a 2500 kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.9 m before stopping. The police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. Part A What was that speed? 2. Relevant equations law of conservation momentum 3. The attempt at a solution so , we have mivii + 0 = m1v1f + m2v2f and since final velocities are same(inelastic collision) m1v1i = vf( m1 +m2 ) or m1( v1i - vf ) = m2vf - (i) kinetic enrgy is not conserved 0.5m1v1i2 = 0.5vf2( m1 + m2 ) taking the mivf2 to the left and since 0.5 cancel m1(v1i2 - vf2) = m2vf2 m1 (v1i + vf)(v1i - vf ) = m2vf2 -(ii) dividing (i) and (II) we get, v1 + vf = vf so from here do i conclude that the final velocities are different otherwise answer makes no sense and instead use subscripts for different final velocities . but final velocity should be same ???? and why is that distance and coefficient of kinetic friction given need help here..