The resistance R of a piece of wire is given by
where
is the resistivity of the material, L is the length of the wire and A is its cross-sectional area.
Using this formula, and labeling with A the aluminum and with T the tungsten wire, we can write the ratio between
(the resistance of the tungsten wire) and
(the resistance of the aluminum wire):
the two wires are identical, so L and A are the same for the two wires and simplify in the ratio, and we get:
By using the resistivity of the aluminum:
and the resistivity of the tungsten:
m we can get the resistance of the tungsten wire:
Answer:
Explanation:
Given that,
First Capacitor is 10 µF
C_1 = 10 µF
Potential difference is
V_1 = 10 V.
The charge on the plate is
q_1 = C_1 × V_1 = 10 × 10^-6 × 10 = 100µC
q_1 = 100 µC
A second capacitor is 5 µF
C_2 = 5 µF
Potential difference is
V_2 = 5V.
Then, the charge on the capacitor 2 is.
q_2 = C_2 × V_2
q_2 = 5µF × 5 = 25 µC
Then, the average capacitance is
q = (q_1 + q_2) / 2
q = (25 + 100) / 2
q = 62.5µC
B. The two capacitor are connected together, then the equivalent capacitance is
Ceq = C_1 + C_2.
Ceq = 10 µF + 5 µF.
Ceq = 15 µF.
The average voltage is
V = (V_1 + V_2) / 2
V = (10 + 5)/2
V = 15 / 2 = 7.5V
Energy dissipated is
U = ½Ceq•V²
U = ½ × 15 × 10^-6 × 7.5²
U = 4.22 × 10^-4 J
U = 422 × 10^-6
U = 422 µJ
1) Answer D not at all
The car is not experiencing any frictional force so that implies that there is no force acting on the car once it starts motion. So, according law of inertia, the car will continue to move and no other force is required.
Friction force is the resistance force that opposes the motion of any object. It arises due to the contact of surfaces.
2) Answer C none
There is no force on any spaceship moving far from any planet. So, according to law of inertia the spacecraft will continue to move at same speed.
Law of inertia states that any object keeps in the state of motion or rest unless a non zero external force is applied on it.
Explanation:
A) use the formula:
B) use the formula:
with angular velocity u calculated in A)
