Answer:
If she stands on the North side of a river flowing to the East at 5 mph,
she must head towards the SouthWest to arrive on the South side of the river directly across from her starting point and we have
x^2 + 5^2 = 10^2 where x is her speed directly across the river
x = (75)^1/2 = 8.66 mph towards the South
sin theta = 5 / 10 = 1/2
She must angle the boat at 30 deg from straight South
1. All the relevant resistors are in series, so the total (or equivalent) resistance is the sum of the resistances of the resistors: 20 Ω + 80 Ω + 50 Ω = 150 Ω [choice A].
2. The ammeter will read the current flowing through this circuit. We can find the ammeter reading using Ohm's law in terms of the electromotive force provided by the battery: I = ℰ/R = (30 V)(150 Ω) = 0.20 A [choice C].
3. The voltmeter will measure the potential drop across the 50 Ω resistor, i.e., the voltage at that resistor. We know from question 2 that the current flowing through the resistor is 0.20 A. So, from Ohm's law, V = IR = (0.20 A)(50 Ω) = 10. V, which will be the voltmeter reading [choice F].
4. Trick question? If the circuit becomes open, then no current will flow. Moreover, even if the voltmeter were kept as element of the circuit, voltmeters generally have a very high resistance (an ideal voltmeter has infinite resistance), so the current moving through the circuit will be negligible if not nil. In any case, the ammeter reading would be 0 A [choice B].
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
