Given :-
- A car of mass 1000 kg is heading east at 25 m/s.
- It collides with a car of mass 1200 kg heading north at 30 m/s.
- When the cars collide, they stick together.
To Find :-
- At what angle do the cars move after the collision?
Solution :-
Here it's given that a car of mass 1000kg moving with velocity of 25m/s North . Another car of mass 1200kg is moving with velocity 30m/s East.
So that ,

And ,

See attachment .
From Triangle law of vector addition , the resultant of both vectors will be given by third side of the triangle taken in opposite direction.
So , if the resultant velocity makes an angle
. Then ,
Substituting the respective values,
Simplify ,
Take arctan both sides ,
Hence the cars move at an angle of tan-¹(6/5) NE after the collision .