Answer:
Explanation:
A) 131 dB = 10*log(I / 1e-12W/m²)
where I is the intensity at 2.6 m away.
13.1 = log(I / 1e-12W/m²
1.25e13= I / 1e-12W/m²
I = 1.25 x10^1W/m²
power = intensity * area
P = I * A = 12.5W/m² * 4π(2.6m)² =1061 W ◄
B) 86 dB = 10*log(I / 1e-12W/m²)
8.6 = log(I / 1e-12W/m²)
3.98e8 = I / 1e-12W/m²
I = 3.98e-4 W/m²
area A = P / I = 1061W / 3.98e-4W/m² = 2.66e6 m²
A = 4πr²
2.66e6 m² = 4πr²
r = 14.5m ◄
Answer:
The work done by Joel is greater than the work done by Jerry.
Explanation:
Let suppose that forces are parallel or antiparallel to the direction of motion. Given that Joel and Jerry exert constant forces on the object, the definition of work can be simplified as:
Where:
- Work, measured in joules.
- Force exerted on the object, measured in newtons.
- Travelled distance by the object, measured in meters.
During the first 10 minutes, the net work exerted on the object is zero. That is:
In exchange, the net work in the next 5 minutes is the work done by Joel on the object:
Hence, the work done by Joel is greater than the work done by Jerry.
Answer:
1. Urea, (d)Fertilizer
2. Combines, (c) Harvesting and threshing
3. Silos, (b) Storage of grains
4. Seed drills, (a) Sowing seeds
5. Irrigation, (f) Sprinklers
6. Tilling, (e) Preparation of soil
Explanation:
1) Urea is a widely used and important fertilizer in the agricultural industry
2) The combine harvester combines three categories of harvesting grain drops such as threshing reaping and winnowing
3) Silos are used to store grains
4) A seed drill is a seed planting mechanism for burying seeds to a particular depth during seed planting
5) Irrigation is the application of required volume of water to plants
6) Tilling is the digging, turning, and staring operations meant to prepare the soil.
A.radioactive isotopes are used to detect medical problems.
C.Radioactive isotopes are used to treat some diseases.
D.radiation is used to kill cancer cells.
The vast majority of an atom is indeed empty space. Most of it's mass is centered in the nucleus. Flying around the nucleus are the electrons, but they're very far away. Most of the atom is the space between the nucleus and the electrons.<span />
