Let F = the downstream speed of the water.
<span>Then the boat's upstream speed is: 15 - F </span>
<span>The boat's downstream speed is: 15 + F </span>
<span>Assume both the journeys mentioned take T hours, then using "speed x time = distance" we get: </span>
<span>Downstream journey: (15 + F)T = 140 </span>
<span>Upstream journey: (15 - F)T = 35 </span>
<span>Add the two formulae together: </span>
<span>(15 + F)T + (15 - F)T = 140 + 35 </span>
<span>15T + FT + 15T - FT = 175 </span>
<span>30T = 175 </span>
<span>T = 35/6 </span>
<span>Use one of the equations to find F: </span>
<span>(15 + F)T = 140 </span>
<span>15 + F = 140/T </span>
<span>F = 140/T - 15 </span>
<span>F = 140/(35/6) - 15 </span>
<span>F = 24 - 15 </span>
<span>F = 9 </span>
<span>i.e. the downstream speed of the water is 9 kph </span>
<span>Therefore, the boat's speed downstream is 15 + F = 15 + 9 = 24 kph.
the answer is: *24kph*</span>
The scientific question can be supported by evidence that must be true of the possible answers to a scientific question. Option D is correct,
<h3>What is a Scientific hypothesis?</h3>
A scientific hypothesis must meet two criteria, A scientific hypothesis must be testable, and a scientific hypothesis must be falsifiable The basic idea of a hypothesis is that there is no predetermined outcome.
For a solution to be termed a scientific hypothesis, it has to be an idea that can be supported or refuted through carefully crafted experimentation or observation.
Only scientific questions may be answered by scientific activity. The design of the research is also influenced by scientific issues.
The scientific question can be supported by evidence that must be true of the possible answers to a scientific question.
They are accurate regarding the scientific question and can be substantiated by proof.
Hence option D is correct.
To learn more about the hypotheses refer to the link ;
https://brainly.in/question/1769011
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Answer:
doubled
Explanation:
F=ma1----------(1)
2F = ma2-------(2)
Divide 2nd equation by 1st one
we get a1×2=a2
By definition,
q = 1.22y/D
Where,
q = min. angle
y = wavelength
D = Aperture diameter = diameter of the antenna
At distance "x" from the antenna,
L =xq = 1.22xy/D
Where, L = Min. distance
But, y =c/f = (3*10^8)/(16*10^9) = 0.01875 m
Substituting;
L = 1.22*5*10^3*0.01875/2.1 = 54.46 m
Answer:
If there are no forces acting upon the object, then there is no acceleration. If there is no acceleration, then the object will move with a constant velocity.
Explanation:
