If the police are chasing a runaway car why is knowing the velocity of the car important

If you only know its speed, that's not enough information to catch it. You could even chase it at DOUBLE that speed, and you'd never catch it if you were chasing in the wrong direction.

You also have to know the DIRECTION the runaway car is going, so that you can chase in the same direction.

Now that you know its speed AND direction, you know its velocity. You need that information to have any chance of catching it.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards