Weeds are very important agronomically because they reduce the yield of crops in three ways: by competing with the crop for water, light and nutrients, by interfering with crop harvest, and by contaminating harvested products with weed seeds and toxins. Weeds can reduce yield up to 50% and are responsible for millions of dollars in crop losses each year.
It’s biotic factor would be competition as Competition can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another.
Answer:
B. Observation
Explanation:
Using a thermometer to read the temperature of a solution is tantamount to the making an observation.
Observation are recorded using our senses of sight, taste, earing, feeling etc or by the use of instrument.
- Through observation, data is usually collected to make inferences about an experiment.
- An observation leads to the formulation of a hypothesis which is scientific guess that leads to experimental designs.
- Conclusions are drawn from the information of data obtained from an experiment.
<span>haha I used to think biology was so hard, i find it quite easy now.
Okay, so basically Osmosis is the movement of water molecules from a higher concentration to a lower concentration. Diffusion is generally the movement of a gradient from higher concentration to an area of lower concentration. Osmosis applies to water only, whereas diffusion, you have many types such as Passive transport [ movement of molecules from high- low, NO CELLULAR ENERGY needed! ] then you have faciliated diffusion ( basically uses a channel protein to allow big substances to go through the membrane : NO ENERGY needed]
OSMOSIS, the important thing to remember is that water ALWAYS flow towards the region with the higher concentration of the solute (ex: Salt is solute, water is solvent) solute is the thing that is being dissolved. Solvent is the one doing the dissolving. Hope this helped!</span>
Answer: the constant angular velocity of the arms is 86.1883 rad/sec
Explanation:
First we calculate the linear velocity of the single sprinkler;
Area of the nozzle = π/4 × d²
given that d = 8mm = 8 × 10⁻³
Area of the nozzle = π/4 × (8 × 10⁻³)²
A = 5.024 × 10⁻⁵ m²
Now total discharge is dived into 4 jets so discharge for single jet will be;
Q_single = Q / n = 0.006 / 4 = 1.5 × 10⁻³ m³/sec
So using continuity equation ;
Q_single = A × V_single
V_single = Q_single/A
we substitute
V_single = (1.5 × 10⁻³) / (5.024 × 10⁻⁵)
V_single = 29.8566 m/s
Now resolving the forces as shown in the second image,
Vt = Vcos30°
Vt = 29.8566 × cos30°
Vt = 25.8565 m/s
Finally we calculate the angular velocity;
Vt = rω
ω_single = Vt / r
from the given diagram, radius is 300mm = 0.3m
so we substitute
ω_single = 25.8565 / 0.3
ω_single = 86.1883 rad/sec
Therefore the constant angular velocity of the arms is 86.1883 rad/sec