Answer:
During the section CD , the speed is fastest.
Explanation:
The rate of change of distance is called speed.
Speed = distance / time
Its SI unit ism/s. It is a scalar quantity.
The slope of the distance time graph is given by the speed of the object.
Here, the speed of AB is 30/3= 10 m/s .
The speed of BC is = 0 m/s
The speed of CD is (50 - 30)/(6 - 5) = 20 m/s
So, the speed is maximum during the section CD.
Answer:
A low difference in the concentration of the molecule across the media
Explanation:
Diffusion is a type of passive transport where the molecules move in the influence of concentration gradient of diffusing molecules i.e. from the higher concentration region to the lower concentration region. There are some factors which affect the rate of diffusion, these are written below -
- Mass of diffusing molecule - lighter molecules diffuse faster and heavier one diffuse relatively slower.
- Concentration gradient - rate of diffusion is higher if the difference in concentration of the diffusing particles is larger in the two regions.
- Distance traveled - molecules diffuse faster if they need to travel little distance during diffusion.
- Temperature - rate of diffusion will be greater at higher temperatures because the movement of diffusing molecules gets increased.
- Solvent density - rate of diffusion tend to be lower if the solvent has higher density.
Looking at these factors we can conclude that the second statement in the question tells about a negative impact regarding the diffusion because due to low difference in concentration across the two media, the rate of diffusion will be lower.
Answer:
2200000 = 2.2E6 min for light from Proxima to reach earth
8.3 min from light sun to reach earth
2.2E6/8.3 = 2.56E5 times for light from Proxima
Proxima is about 256,000 times farther away than the sun
Since the sun is about 93,000,000 = 9.3E7 miles from earth
Proxima is then 9.3E7 * 2.56E5 = 2.4E13 miles away
Note - the speed of light is
3.00E8 m/s * 60 s/min / 1000 m/km = 1.8E7 km/min as given
