The equation of our ellipse is:
(1)
First, let's reduce the equation of the ellipse to the standard form:
To do that, we should divide both terms of equation (1) by 6400, and we get:
This is a vertical ellipse (because 
) centered in the origin, and so the distance of its foci from the origin (on the y axis) is given by
Therefore, the position of the two foci is (0,6) and (0,-6)
Answer:
The voltage of the generator is 88.53volts
Explanation:
The voltage across the RLC AC circuit will be the voltage across the generator. It is expressed as
V = IZ and
Z² = R² + (Xl-Xc)²
Z = √R² + (Xl-Xc)² where;
Z is the impedance that oppose the flow of current in the resistor, capacitor and inductor in the circuit
I is the total current = 0.312A
R is the resistance in the circuit = 280ohms
Xl is the inductive reactance = 508ohms
Xc is the capacitive reactance = 315ohms
Substituting to this parameters to get the impedance Z we have;
Z = √280²+(508-315)²
Z = √208²+(193)²
Z = √80,513
Z = 283.75ohms
The voltage V of the generator = current × impedance
V = 0.312×283.75
V = 88.53Volts
The voltage if the generator is 88.53volts
Density formula is:
D = m / V
Volume of the matchbox car:
V = 46 ml - 41 ml = 5 ml = 0.005 l = 0.005 dm³
D = 10 g / 0.005 dm³
D = 2000 g / dm³ = 2 kg / dm³ = 2 × 10 ^(-3) kg/m³
