Answer:
θ = 61.3°
She must swim at an angle of 61.3°
Explanation:
Given;
Width of river = 100 m
Alicia speed in still water = 2.5m/s
Current of river = 1.2m/s
The angle for her to achieve her goal can be derived by the summation of velocity in the direction of the current.
Her speed in the opposite direction of the current must be able to neutralise the speed of the current;
2.5cosθ - 1.2 = 0
2.5cosθ = 1.2
cosθ = 1.2/2.5
θ = cosinverse(1.2/2.5)
θ = 61.3°
By velocity vectors (arrow)
To solve this problem we will apply the relation of Ohm's law, at the same time we will use the concept of resistance in a cable, resistivity and potential difference.
According to Ohm's law we have to
Here,
V = Voltage
I = Current
R = Resistance
At the same time resistance can be described as
Here,
= Resistivity of the material
l = Length of the specimen
A = Cross-sectional area
From the above expression we can write the current as,
Replacing we have that,
Therefore the current in the wire is 3.809A
<em>Note: The value obtained for the resistivity of Tungsten was theoretically obtained and can be consulted online.</em>
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