What the original source of the energy that transfers through the food web to a meat eating animals such as a cat

The sun is the original source of energy

because the plants feed from the sun and the animals eat the plants and then the animals eat the plant eating animals.

To draw the resultant vector, join the tail of the first vector with the second vector's head and put the arrowhead. To determine the magnitude, measure the length of resultant R, and to find out the direction, measure the angle of the resultant with the x-axis.