Answer:
Explanation:
We know that Impulse = force x time
impulse = change in momentum
change in momentum = force x time
Force F = .285 t -.46t²
Since force is variable
change in momentum = ∫ F dt where F is force
= ∫ .285ti - .46t²j dt
= .285 t² / 2i - .46 t³ / 3 j
When t = 1.9
change in momentum = .285 x 1.9² /2 i - .46 x 1.9³ / 3 j
= .514i - 1.05 j
final momentum
= - 3.1 i + 3.9j +.514i - 1.05j
= - 2.586 i + 2.85j
x component = - 2.586
y component = 2.85
Answer: C- ecosystem
An ecosystem is a biological community in which living beings interacts with their non-living environment. An ecosystem consists of abiotic ( non-living factors like water, sunlight, wind and soil) and biotic factors such as plants and animals. Ecosystem allows not only the interaction of abiotic and biotic factors but it favors the interaction between the living species. For example animals are dependent upon plants so as to derive their food. The coexistence of organisms favors the diversity of land forms on earth.
Communities of organisms coexist in organized, balanced ecosystems.
Answer:
0.906
Explanation:
Let g = 9.81 m/s2. We can calculate the rate of change in potential energy when m = 201kg of water is falling down a distance of h = 131m per second

So the efficiency of the water turbine is the ratio of output power over input power:

Answer:
The boats are 934.65 feet apart
Explanation:
Given:
The angles of depression to the two boats are 42 degrees and 29 degrees
Height of the observation deck i = 1,353 feet
To Find:
How far apart are the boats (y )= ?
Solution:
<em><u>Step 1 : Finding the value of x(Refer the figure attached)</u></em>
We can use the tangent ratio to find the x value


x = 590.47 feet
<em><u>Step 2 : Finding the value of z (Refer the figure attached)</u></em>


z = 1525.12 feet
<em><u>Step 3 : Finding the value of y (Refer the figure attached</u></em>)
y = z -x
y = 1525.12 - 590.47
y = 934.65 feet
Thus the two boats are 934.65 feet apart