Electric current is the movement of electrons through a wire. Electric current is measured in amperes (amps) and refers to the number of charges that move through the wire per second.
Convection is the process of heat transfer in fluids by the actual motion of matter. It happens in liquids and gases. It may be natural or forced. It involves a bulk transfer of portions of the fluid.
Hope that helps
The displacement is a vector that is calculated by subtracting the final and initial positions of an object that has made a movement.
We know that initially the object was at the origin and moved to the -8m position.
Suppose that the movement was made on the x-axis. So:
d = [-8 - (0)]x
d = -8x
Regarding the second question.
When the acceleration is constant then the speed changes at a constant rate. Therefore the graph of velocity vs. time will look like a line with a negative slope (if the acceleration is negative) or a line with a positive slope (if the acceleration is positive)
For example. Suppose that the acceleration of gravity is 10
Now suppose you drop an object from a building.
At the initial moment (second 0) the speed is 0 m/s.
After 1 second the speed of the object will be 10 m/s.
After 2 seconds the speed of the object will be 20 m/s.
After 4 seconds the speed will be 40 m/s.
The graph of this example is shown in the attached figure. Note that it is a straight line.
When we talk about that the sun rises and sets, an individual on the surface of the earth who is motionless or stationary is the spectator or observer. The observer may perhaps be on the moon to see that the sun does not travel all over Earth every 24 hours.