Technician A says that a common cause of parking brakes that will not hold, is out of adjustment slack adjusters. Technician B s
1 answer:
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Answer:
The distance the train travels before coming to a (complete) stop = 40/81 km which is approximately 493.83 meters
Explanation:
The initial speed of the train u = 80 km/h = 22 2/9 m/s = 22. m/s
The magnitude of the constant acceleration with which the train slows, a = 0.5 m/s²
Therefore, we have the following suitable kinematic equation of motion;
v² = u² - 2 × a × s
Where;
v = The final velocity = 0 (The train comes to a stop)
s = The distance the train travels before coming to a stop
Substituting the values gives;
0² = 22.² - 2 × 0.5 × s
2 × 0.5 × s = 22.²
s = 22.²/1 = 493 67/81 m = 40/81 km
The distance the train travels before coming to a (complete) stop = 40/81 km ≈ 493.83 m.
<h2>Answer:</h2>
(a) 3.18Ω
(b) 3.18Ω
<h2>Explanation:</h2>Let the two bulbs be A and B
Given;
= Resistance in bulb A = 3.0Ω
= Resistance in bulb B = 2.5Ω
Since the two bulbs are connected in parallel;
i. their effective resistance () is given by
=
+
---------------(i)
Substitute the values of and
into equation (i)
=> =
+
Solve for
= 1.36Ω
ii. voltage (potential difference), V, across them is the same;
Therefore we can get the total current (I) that will flow through them if the voltage to be supplied is 2.4V.
Use the Ohm's law;
V = I x R -----------------(ii)
Where;
V = voltage across them = 2.4V
I = total current flowing through them
R = their effective resistance = = 1.36Ω
Substitute these values into equation (ii) as follows;
2.4 = I x 1.36
I = 2.4 / 1.36
I = 1.76A
(a) Now get the value of R
Since the voltage across the two bulbs is 2.4V out of the 8.0V supplied by the source, then the remaining (8.0 - 2.4 = 5.6)V will pass across the resistor R.
Also, since the two bulbs make a series connection with the resistor R, the same total current (I = 1.76A) that flows through these bulbs will flow through the resistor R.
Therefore, to get the value of R, we use the relation
V = I x R ------------------------------(iii)
Where;
V = voltage across the resistor = 5.6V
I = current through the resistor = 1.76A
<em>Substitute these values into equation (iii)</em>
=> 5.6 = 1.76 x R
=> R = 5.6 / 1.76
=> R = 3.18Ω
Therefore, the value of R to be chosen in order to supply each bulb with a voltage of 2.4V is 3.18Ω
(b) The potential difference and voltage across refer to the same thing. Therefore, the value of R that would make the potential difference across each of the bulbs be 2.4V is the same as the one calculated in (a) which is 3.18Ω