Answer:
x=45
Explanation:
by taking 42 and dividing it by 14 you get 1/3, because 14 is 1/3 of 42 you can then see that the ratio is multiplied by 3. si then you can just multiply 15 by 3 to get 45
Answer:

Explanation:
<u>Capacitance</u>
A two parallel-plate capacitor has a capacitance of

where

A = area of the plates = 
d = separation of the plates

We need to compute C. We'll use the circuit parameters for that. The reactance of a capacitor is given by

where w is the angular frequency

Solving for C

The reactance can be found knowing the total impedance of the circuit:

Where R is the resistance,
. Solving for Xc

The magnitude of the impedance is computed as the ratio of the rms voltage and rms current

The rms current is the peak current Ip divided by
, thus


Now collect formulas

Or, equivalently



The capacitance is now

The radius of the plates is

The separation between the plates is



Answer:
The length of line is 78 cm or 0.78 m.
Explanation:
initial reading 2 mark
final reading 80 cm
The length of the line
= final reading - initial reading
= 80 - 2
= 78 cm
1 cm = 0.01 m
So, 78 cm = 0.78 m
1st derivative gives velocity;
d r(t)/ dt = 2t i + 6 j + 4/t k
2nd derivative gives acceleration;
d^2 r(t)/ dt^2 = 2 i - 4/ t^2
Speed ;
Square root of (4 t^2 + 36 + 16/ t^2)
For a given time, like 2 seconds, t will be 2. And answer of speed will be scalar.