Which of the following not affected by friction?
1:Ma
2VR
3:Efficiency
4:All of these​

What is the final velocity of the initial velocity of 25 and -50?

Why should seat belts not be mandatory quick plz

A980-kg sports car collides into the rear end of a 2300-kg suv stopped at a red light. the bumpers lock, the brakes are locked, and the two cars skid forward 2.6m 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. what was that speed?