A car is travelling at 80km/h in east direction , a train is travelling at 50 m/s in north direction then what is the combined velocity of car and train?

Answer 1

They should be asking for what is the velocity of the car with respect to the train, or vice versa. The "combined velocity" is the vector sum. The relative velocity is the vector difference.

In this case, they both have the same magnitude. Use the Pythagorean theorem, since the separate velocities are at right angles.

Answer 2

. A 2000 kg car traveling at 8.0 m/s has a rear-end collision with a 1500 kg car stopped at a traffic light. The cars lock bumpers and skid off together.
a. Which of the ranges below is correct for the resulting velocity?