Main sequence stars are characterised by the source of their energy.They are all undergoing fusion of hydrogen into helium within their cores. The mass of the star is the main element for such process or phenomenon to take place for it is a determinant of both the rate at which they perform the said activity and the amount of fuel available.
To answer the question, the lower mass limit for a main sequence star is about 0.08. If the mass of a main sequence star is lower than the above-mentioned value, there would be a deficit or insufficiency of gravitational force to generate a standard temperature for hydrogen core fusion to take place and the underdeveloped star would form into a brown dwarf instead.
<span>The last option.
Plants absorb carbon dioxide from the atmosphere, water from the soil and other nutrients also from the soil - salts containing nitrogene, potassium, sulphur, etc. They use water and carbon dioxide to produce sugar through photosyntesis.
Decomposition is the reaction that converts any organic compound back into inorganic compounds - water, carbon dioxide and salts containing nitrogene, potassium, sulphur, etc. So it's basically the opposite.
So photosyntesis uses carbon dioxide as a reactive and take it from the atmosphere, whereas decomposition generates carbon dioxide as a product and releases it to the atmosphere.</span>
Answer:
The spring was compressed the following amount:

Explanation:
Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount
), and the total final energy is the addition of the kinetic energies of both masses:



Answer:
1.52 seconds
Explanation:
Step 1: identity the given parameters
Initial velocity (u) = 12m/s
Height above ground (h1) = 4m
Final velocity (V) = 0
Step 2: calculate the height travelled by the object from 4m height (h2).
V^2 = U^2 -2gh
0= 12^2-2(9.8*h)
2(9.8*h) = 12^2
19.6*h = 144
h = 144/19.6
h = 7.347 m
Total height above ground (ht) = 4m +7.347m = 11.347m
Step 3: calculate the time reach ground
T = √(2h/g)
T = √(2*11.347/9.8)
T= √(22.694/9.8)
T= √2.316
T= 1.52 seconds