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:
The genetic makeup in a organism.
Explanation:
Answer:
m' = 1 x 10⁻⁶ kg/s
Explanation:
Given that
Diffussion constant = 1 x 10⁻¹¹
Mass flow rate ,m = 2 x 10⁻⁶ kg/s
The diffusion is inversely proportional to the thickness of the membrane and therefore when the thickness is doubled, the mass flow rate would become half.
So new flow rate m'
m' = 1 x 10⁻⁶ kg/s
Let's apply an equation of equilibrium to the situation: The sum of the moments about the left end of the board must equal 0.
We have three moments to add. Positive force values indicate upward direction and negative values indicate downward direction. All distances given below are measured to the right side of the left end of the board:
- The weight of the board, -125N, located at 2m (center of the board due to its uniform density)
- The tension in the right chain, +250N, located at 4m
- The weight of the person, -500N, located at a distance "x"
The sum of the moments must equal 0 and is given by:
ΣFx = 0
F is the magnitude of force, x = distance from the left end of the board
Plug in all of the force and distance values and solve for x:
ΣFx = 250(4) - 125(2) - 500x = 0
500x = 750
x = 1.5m
