Here I and j are unit vectors of xy coordinates.

Generally speaking, (x, y)=xi+yj.

This problem means that the coordinate in the x direction is x=2t.

In the y direction, y = 2-t 2.

We know that speed is equal to the derivative of position coordinates.

So the velocity Vx=2 in the X direction is 2.

The velocity in the y direction vy =-2t.

After the analysis, we began to do the problem. ...

(1) trajectory equation is represented by x and y.

Then x = 2ty = 2-t 2.

So t = x/2; t^2=(x/2)^2

y=2-(x/2)^2=2-x^2/4

So y = 2-(x 2)/4.

This is the trajectory.

(2) The position vector is the vector (x, y)

We bring in t=0 and t=2, and we know xy.

T=0 x=0 y=2 At this point, the position vector is the vector (0,2).

T=2 x=2 y=-2 position vector (2, -2)

(3) Displacement is a variable of position.

First calculate the displacement:

Displacement vector = end position vector-initial position vector

=(2,-2)-(0,2)=(2,4)

Radial increment refers to the distance increment from the origin.

Increment d = sqr (2 * 2+-(2 *-2))-sqr (0+2 * 2) = sqr8-2 = 2sqr2-2.

All the above units are m.

The landlord should read more books, which is very basic.