The answers are as follows:
64. SKELETAL MUSCLES
Body location: it is usually attached to the bone or to the skin.
Microscopic anatomy: it is made up of very long, cylindrical multinucleated cells which are striated.
Regulation of contraction: the nervous system controls the voluntary contraction of the skeletal muscles.
Speed of contraction: the speed of contraction ranges from slow to fast.
Rhythmicity: the skeletal muscle is arrhythmic.
SMOOTH MUSCLES
Body location: found in the wall of hollow visceral organs [not including those of the heart].
Microscopic anatomy: made up of single fusiform, uninucleated cells that are without striation.
Regulation of contraction: smooth muscles undergo involuntary contractions which are controlled by the nervous system and hormones.
Speed of contraction: very slow. it is the slowest of the three muscles.
Rhythmicity: rhythmic.
CARDIAC MUSCLES
Body location: located in the wall of the heart.
Microscopic anatomy: it is composed of branching chains of cells, that are uninucleated; they are striated and posses intercalated discs.
Regulation of contraction: Undergo involuntary contractions, which are controlled by nervous system, heart pacemarker and hormones.
Speed of contraction: slow.
Rhythmicity: rhythmic.
65. Aging brings about gradual loss in muscle functions. As one grows older, there are usually age related alterations in the skeletal muscle functions. The factors that affect the rate of muscle loss are sex and level of muscle activity. Loss of muscle mass also occurs as one grows older.
66. The sliding filament theory states that, during contraction the thin filaments slide past the thick filaments and the sacomere shortens.
During contraction, the myosin head attaches to the myosin binding site on the actin filament. Using energy from ATP, the myosin head move toward the center of the sacomere, attaching and detaching several times. As a result of this, the thin actin filament is pulled toward the center of the sacomere. This leads to the shorten of the muscle cells.
Explanation:
Given:
x₀ = 0 m
v₀ = 4.2 m/s
t = 11.6 s
a = 2.3 m/s²
Find: x
x = x₀ + v₀ t + ½ at²
x = 0 m + (4.2 m/s) (11.6 s) + ½ (2.3 m/s²) (11.6 s)²
x ≈ 203 m
Round as needed.
Answer:
Part a) Big bang occurred about 13.8 billion years ago. This time is arrived after see the shift in the cosmic background radiation that fills the universe. The result of the big bang was the creation of universe itself. Everything we know space, matter, time was created by the event thus giving birth to the universe and stars, galaxies,e.t.c.
Part b) No string theory is currently not proven as of yet. The basic problem in formulating the theory of everything is to mix 2 completely different theories known as quantum theory of matter and theory of relativity. But this has not been achieved as of yet. There are different theories that try to explain the both quantum and relativistic nature of the matter and string theory is one of the theories that has been proposed to explain the same.The theory is not completely developed as of yet as there are numerous inconsistencies with it such as it proposes 34 dimension's of nature which have not been observed as yet.Also there is an inherent nature of the theory that it deals with quantities with scales of length making it impossible to verify the theory which still is mathematically incomplete.
Part c) Strong Nuclear forces come into action in the nucleus of an atom and holds the nucleon's together. As we know that a pair of protons will repel due to nature of their charge the strong nuclear force holds them together.
Part d) Cosmology is the branch of astronomy that deals with the origin and evolution of the universe. It basically is the study about the universe was formed and how it evolved during different stages.
Answer: 60m/s
Explanation:
From the diagram:
Θ = 30°
Vertical resolution (y-axis) :
Voy = VoSinΘ
g in the upward direction = negative (-) = - g
Vfinal = 0
Distance (H) traveled along y =
Time taken to reach maximum height :
From v = u + at
0 = usinΘ - gt
gt = usinΘ
t = usinΘ / g
Horizontal resolution:
S = ut + 1/2at^2
Substituting t = usinΘ / g ; Voy = usinΘ
S = (usinΘ × usinΘ / g) - 1/2 g × (usinΘ /g)^2
S = (u^2sin^2Θ / g) - (u^2sin^2Θ / 2g)
S = (u^2sin^2Θ) / 2g
Now if S = maximum height = 45m
Then,
45 = [Vo^2sin^2(30°)] / 2(10)
45 =[ Vo^2 * (0.5)^2] / 20
45 =( Vo^2 * 0.25) / 20
20 * 45 = Vo^2 * 0.25
900 / 0.25 = Vo^2
3600 = Vo^2
Vo = sqrt(3600)
Vo = 60m/s
Answer:
v= 17.15 m/s
Explanation:
mass of the book=0.1 Kg
height above ground, h= 15 m
Using conservation of energy
Potential energy is converted into kinetic energy
v= 17.15 m/s
Hence, the book will hit the ground at the speed of 17.15 m/s.