Answer:
V = 6.65 [volt]
Explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
![P=E/t\\P = 40/30\\P = 1.33[s]](https://tex.z-dn.net/?f=P%3DE%2Ft%5C%5CP%20%3D%2040%2F30%5C%5CP%20%3D%201.33%5Bs%5D)
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.

where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
![V = 1.33/0.2\\V = 6.65 [volt]](https://tex.z-dn.net/?f=V%20%3D%201.33%2F0.2%5C%5CV%20%3D%206.65%20%5Bvolt%5D)
Answer:
magnitude=34.45 m
direction=
Explanation:
Assuming the initial point P1 of this vector is at the origin:
P1=(X1,Y1)=(0,0)
And knowing the other point is P2=(X2,Y2)=(19.5,28.4)
We can find the magnitude and direction of this vector, taking into account a vector has a initial and a final point, with an x-component and a y-component.
For the magnitude we will use the formula to calculate the distance
between two points:
(1)
(2)
(3)
(4) This is the magnitude of the vector
For the direction, which is the measure of the angle the vector makes with a horizontal line, we will use the following formula:
(5)
(6)
(7)
Finding
:
(8)
(9) This is the direction of the vector
Use the equation

then sub in the variables

solve
your answer is 1000 Newtons
Answer:

Explanation:
Most of the power developed by the engine is used to compensate for the mechanical energy loss due to frictional forces because these are the only forces on the horizontal direction the automobile is subjected to, besides of that generated by the engine itself. If the automobile is moving at constant speed, then these the force the engine provides is equal to the total friction force acting on the car.
We calculate then the force the engine provides. We know that power relates to work by the equation
, and that work relates to force by the equation
, so combining them we have:

Which can be written as:

And since
are
, for our values the force the engine provides is:

Which is also then the total friction force acting on the car.