Answer:


Explanation:
When coefficient of friction is approximately zero then we have



here we know that

R = 30 m


now when friction coefficient is 0.30 then we have


now we have




The answer is <span>It protects the seed until it matures.
Through the process of elimination:
- </span><span>It protects the seed until it matures. YES. A female pine cone the unfertilized seeds until they become mature. Then, the cone opens and seeds fall out of the cone.
</span><span>- It makes food for the adult plant. NO. The food of plants in made of green leaves that contain chlorophyll in the process of photosynthesis.
- It allows for photosynthesis to occur. NO. The cones have nothing to do with photosynthesis but they are responsible for reproduction.
- It acts as an object to attract birds. NO. The birds look for colourful flowers while cones are woody.
- It serves as an ornamental object on the tree. NO. Every part of plants has more important function than serving as an ornamental object.</span><span>
</span>
Not sure this is a physics question (probably biology).
Anyway, the correct answer is A):
"Plasticity helps us to adapt to our environment. It also generally decreases with age".
Plasticity is the ability to adapt to the environment. Since this ability is linked with brain functions, and brain functions worsen with age, then plasticity decreases with age.
Answer:
The answer to the question is
The roller coaster will reach point B with a speed of 14.72 m/s
Explanation:
Considering both kinetic energy KE = 1/2×m×v² and potential energy PE = m×g×h
Where m = mass
g = acceleration due to gravity = 9.81 m/s²
h = starting height of the roller coaster
we have the given variables
h₁ = 36 m,
h₂ = 13 m,
h₃ = 30 m
v₁ = 1.00 m/s
Total energy at point 1 = 0.5·m·v₁² + m·g·h₁
= 0.5 m×1² + m×9.81×36
=353.66·m
Total energy at point 2 = 0.5·m·v₂² + m·g·h₂
= 0.5×m×v₂² + 9.81 × 13 × m = 0.5·m·v₂² + 127.53·m
The total energy at 1 and 2 are not equal due to the frictional force which must be considered
Total energy at point 2 = Total energy at point 1 + work done against friction
Friction work = F×d×cosθ = (
× mg)×60×cos 180 = -117.72m
0.5·m·v₂² + 127.53·m = 353.66·m -117.72m
0.5·m·v₂² = 108.41×m
v₂² = 216.82
v₂ = 14.72 m/s
The roller coaster will reach point B with a speed of 14.72 m/s