Answer:
3 km/h
Explanation:
Let's call the rowing speed in still water x, in km/h.
Rowing speed in upstream is: x - 2 km/h
Rowing speed in downstream is: x + 2 km/h
It took a crew 9 h 36 min ( = 9 3/5 = 48/5) to row 8 km upstream and back again. Therefore:
8/(x - 2) + 8/(x + 2) = 48/5 (notice that: time = distance/speed)
Multiplying by x² - 2², which is equivalent to (x-2)*(x+2)
8*(x+2) + 8*(x-2) = (48/5)*(x² - 4)
Dividing by 8
(x+2) + (x-2) = (6/5)*(x² - 4)
2*x = (6/5)*x² - 24/5
0 = (6/5)*x² - 2*x - 24/5
Using quadratic formula
A negative result has no sense, therefore the rowing speed in still water was 3 km/h
Answer:
Option C: Current X has a lower potential difference than Current Y.
Explanation:
The chart above only shows the potential difference of difference current.
A careful observation of the chart shows that Current X has a lower potential difference than Current Y.
Answer:
We should not consider the needs of humans first because Conservation of nature is more important.
Explanation:
Human beings are important but the priority must be given to nature. Human beings have uncountable needs and if we focus on satisfying all such needs then it will affect our nature. Because finally our needs are fulfilled by using the resources from nature.
So rather than considering the needs of humans first, we must try to preserve our nature as much as possible. It is not done then it will lead to disaster.
(d) Acceleration is a vector quantity
Answer:
15,00kg
Explanation:
here's your solution
=> force = 45,000N
=> acceleration = 30m/s^2
=> mass = ?
=> Mass = force/acceleration
=> mass = 45,000/30
=> mass = 15,00kg
hope it helps
