Answer:
4 m/s
Explanation:
It doesn't state it clearly in the problem, but I assume that the shores of the river are parallel and the man reaches the other side perpendicular from where he started (see attached image).
There are an infinite number of ways the swimmer can go from point A to point B, but the shortest time is of course a straight line. We know that the net speed along this line is 3 m/s. We also know the swimmer's speed is 5 m/s. Since the net velocity vector is perpendicular to the river's velocity, we can use Pythagorean theorem.
vᵣ² + (3 m/s)² = (5 m/s)²
vᵣ = 4 m/s
The water in the river flows at a speed of 4 m/s.
In 1842, Julius Robert Mayer discovered The law of conservation of Energy. It its most compact form, it it now called The first law of Thermodynamics
Energy can neither be created nor destroyed, it can only be changed to another form of energy.
Answer:
I prefer to have a bottle filled with hot water
Explanation:
I would prefer to have a bottle filled with hot water instead of an equal mass of nails at the same temperature, since water has higher specific heat than iron (nails). The higher the specific heat of a substance, the more heat it will emit when cooling down and it will take longer to cool. Therefore, water is the best option.
Observation: You saw/ observed something and you are stating that.
Inference: You are predicting something to be true. If so and so, then this will occur.
Answer:
Therefore,
Current required is , I
Explanation:
Given:
Turns = N = 1140
length of solenoid = l = 0.415 m
Magnetic Field,
To Find:
Current , I = ?
Solution:
If N is the number of turns in the length, the total current through the rectangle is NI. Therefore, Ampere’s law applied to this path gives
Where,
B = Strength of magnetic field
l = Length of solenoid
N = Number of turns
I = Current
Therefore,
Substituting the values we get
Therefore,
Current required is , I