Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
The sun's intensity for an outer planet located at a distance 6r from the sun is 5.55 W/m². The result is obtained by using the inverse square law formula.
<h3>What is the Inverse Square Law formula?</h3>
The Inverse Square Law formula describes the intensity of light is inversely proportional to the square of the distance. It can be expressed as

Where
- I₁ = Intensity at distance 1 (W/m²)
- I₂ = Intensity at distance 2 (W/m²)
- d₁ = distance 1 from a light source (m)
- d₂ = distance 2 from a light source (m)
Given the case the sun's intensity is 200 W/m² for an inner planet at the distance r. If an outer planet is at a distance 6r, what is the sun's intensity?
By using the inverse square law formula, the sun's intensity for an outer planet is




I₂ = 5.55 W/m²
Hence, the sun's intensity for a planet at a distance 6r from the sun is 5.55 W/m².
Learn more about intensity of light here:
brainly.com/question/13155277
#SPJ4
First , ocean currents are actually big convection currents moving heat around. Second, ocean currents moves food and nutrients from deeper water in a process called upwelling.
The Atlantis spacecraft carried the first space lab.
Answer: Option 4
<u>Explanation:
</u>
The first space lab is named as ATLAS 1 which is the abbreviation of Atmospheric Laboratory for Applications and Science. It is a short space lab set up in space to observe the atmospheric changes and other scientific experiments in the outer atmosphere of Earth from space.
It contains hi-tech instruments and facilities. It was a part of Phase I of NASA’s mission to planet Earth. This helped in better understanding of Earth’s outer and inner atmosphere. So, the spacecraft used to carry the ATLAS 1 is named as Atlantis.