Answer:
Rate at which current flows is measured in amperes
Explanation:
The rate of flow of electrons constitutes the current. The electrons flow from lower electric potential to higher electric potential. When there is no potential difference then no electron will flow. The direction of the current and the electron are in opposite direction.
The direction of electron from the negative terminal to the positive terminal. The direction of current is from the positive terminal to the negative terminal.The current is measured in ampere.
The expression for current and the charge is as;
Here, q is the charge, t is the time taken and I is the current.
According to the given problem, Jodi made a list about electric current to help her study for a test. He described that electrons move from areas of low to high electric potential, voltage causes current to flow and movement of electrons is continuous in a current.
But he did error. It should be "rate at which charges flow" instead of rate at which current flow.
Therefore, the option (4) is correct.
Answer:
a)
a = 2 [m/s^2]
b)
a = 1.6 [m/s^2]
c)
xt = 2100 [m]
Explanation:
In order to solve this problem we must use kinematics equations. But first we must identify what kind of movement is being studied.
a)
When the car moves from rest to 40 [m/s] by 20 [s], it has a uniformly accelerated movement, in this way we can calculate the acceleration by means of the following equation:
where:
Vf = final velocity = 40 [m/s]
Vi = initial velocity = 0 (starting from rest)
a = acceleration [m/s^2]
t = time = 20 [s]
40 = 0 + (a*20)
a = 2 [m/s^2]
The distance can be calculates as follows:
where:
x1 = distance [m]
40^2 = 0 + (2*2*x1)
x1 = 400 [m]
Now the car maintains its speed of 40 [m/s] for 30 seconds, we must calculate the distance x2 by means of the following equation, it is important to emphasize that this movement is at a constant speed.
v = x2/t2
where:
x2 = distance [m]
t2 = 30 [s]
x2 = 40*30
x2 = 1200 [m]
b)
Immediately after a change of speed occurs, such that the previous final speed becomes the initial speed, the new Final speed corresponds to zero, since the car stops completely.
Note: the negative sign of the equation means that the car is stopping, i.e. slowing down.
0 = 40 - (a *25)
a = 40/25
a = 1.6 [m/s^2]
The distance can be calculates as follows:
0 = (40^2) - (2*1.6*x3)
x3 = 500 [m]
c)
Now we sum all the distances calculated:
xt = x1 + x2 + x3
xt = 400 + 1200 + 500
xt = 2100 [m]