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2 years ago

In humans, the maintenance of a stable internal temperature is a direct result of

1 answer:

8 0

(1) detection of and reaction to stimuli in the environment (2) digestion of starches and absorption of protein from the internal environment (3) diffusion of water and excretion of glucose to the external environment (4) transport of ATP and locomotion through the environment

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8. Contrast. The energy that can be released during a nuclear fission reaction with the energy that can be released during a nuc

Cloud [144]

8) the energy released by fusion is generally 3 to 4 times larger than with fission. Fission has very few by-products but fusion releases large amounts of radioactive particles because it starts with large nuclei.
9) Alpha particles are 2 protons and 2 neutrons all put together. It's really the nucleus of a helium atom. It is most dangerous if you ingest it but it can be stopped with a sheet of paper so outside the body it's not as dangerous as others and due to its size it can't get very far in the air before hitting air molecules
beta particles are high energy electrons or positrons. They travel further due to their small size but can be stopped by a thin barrier of plastic or wood.
Gamma rays are high frequency photons (light) They are stopped by metal plates and go through human tissue. They are quite dangerous.
10) The mass that is lost in chemical reactions is very small. Solve E=mc² for mass and you get m=E/c². This says the mass you lose is equal to the energy you gained divided by the speed of light squared. c² is a VERY big number so you need a lot of energy produced to notice it. Chemical reactions are simply too inefficient to get that much energy out.
11)You need high temperatures for fusion because you're trying to push two atoms together (to "fuse" them as the name suggests) The electrons in one atom repel the other electrons in the other atoms. When stripped down to only protons, you still have to overcome this repulsion (Coulomb repulsion). High temperatures means high velocity of the particles in the plasma. This gives them enough "oomph" to get close enough to fuse. Once close enough to each other, the nuclear force takes over and overwhelms the Coulomb repulsion and the nuclei fuse and release energy in doing so.

7 0

2 years ago

100 points!!! Please help!!!

Greeley [361]

Answer:

41°

Explanation:

Kinetic energy at bottom = potential energy at top

½ mv² = mgh

½ v² = gh

h = v²/(2g)

h = (2.4 m/s)² / (2 × 9.8 m/s²)

h = 0.294 m

The pendulum rises to a height of above the bottom. To determine the angle, we need to use trigonometry (see attached diagram).

L − h = L cos θ

cos θ = (L − h) / L

cos θ = (1.2 − 0.294) / 1.2

θ = 41.0°

Rounded to two significant figures, the pendulum makes a maximum angle of 41° with the vertical.

7 0

3 years ago

A block of mass M is connected by a string and pulley to a hanging mass m. The coefficient of kinetic friction between block M a

aleksklad [387]

Answer:

a) y = 0.98 t², t=1s y= 0.98 m,

b) he two blocks must move the same distance

c) v = 1.96 m / s, d) a = -1.96 m / s², e) x = 0.98 m

Explanation:

For this exercise we can use Newton's second law

Big Block

Y axis

N-W = 0

N = M g

X axis

T- fr = Ma

the friction force has the expression

fr = μ N

fr = μ Mg

small block

w- T = m a

we write the system of equations

T - fr = M a

mg - T = m a

we add and resolved

mg- μ Mg = (M + m) a

a = $g \ \frac{m - \mu M}{m+M}$

a = $9.8 \ \frac{10- 0.2 \ 20}{ 10 \ +\ 20}$

a = 9.8 (6/30)

a = 1.96 m / s²

a) now we can use the kinematic relations

y = v₀ t + ½ a t²

the blocks come out of rest so their initial velocity is zero

y = ½ a t²

y = ½ 1.96 t²

y = 0.98 t²

for t = 1s y = 0.98 m

t = 2s y = 1.96 m

b) Time is a scale that is the same for the entire system, the question should be oriented to how far the big block will move.

As the curda is in tension the two blocks must move the same distance

c) the velocity of the block M

v = vo + a t

v = 0 + 1.96 t

for t = 1 s v = 1.96 m / s

t = 2 s v = 3.92 m / s

d) the deceleration if the chain is cut

when removing the chain the tension becomes zero

-fr = M a

- μ M g = M a

a = - μ g

a = - 0.2 9.8

a = -1.96 m / s²

e) the distance to stop the block is

v² = vo² - 2 a x

0 = vo² - 2a x

x = vo² / 2a

x = 1.96² / 2 1.96

x = 0.98 m

the time to travel this distance is

v = vo - a t

t = vo / a

t = 1.96 /1.96

t = 1 s

3 0

3 years ago

Sam, whose mass is 75 kg , takes off across level snow on his jet-powered skis. The skis have a thrust of 160 N and a coefficien

Volgvan

Answer:

top speed = 17.25

Total height = 281.19 m

Explanation:

given data

mass = 75 kg

thrust = 160 N

coefficient of kinetic friction = 0.1

solution

we get here frictional force acting that is

frictional force = $\mu *m*g$ .............1

frictional force = 0.1 × 75 × 9.8

frictional force = 73.5 N

and

Net force acting will be F = 160 - 73.5 N

F = 86.5 N

Acceleration in the First 15 second will be

F = ma .........2

86.5 = 75 × a

a = 1.15 m/s²

and

now After 15 second the velocity will be as

v = u + at ..........3

here u is 0

so v will be

V = 1.15 × 15

v = 17.25

and

now we get travels distance S in 15 s

s = u × t + 0.5 × a × t²

here u is 0

so distance s will be

s = 0.5 × a × t²

s = 0.5 × 1.15 × 15²

s = 129.37 m

and

now acceleration acting is

F = $\mu *m*g$

m a = $\mu *m*g$

a = $\mu* g$

a = - 0.98

here it is negative it mean downward nature of acceleration

and

now we get distance s by this formula

V² - u² = 2 a s

here v velocity is 0 and

u initial velocity is 17.25 m/s

put here value

0 - 17.25² = 2 × (-0.98) × s

solve it we get

s = 151.82 m

Total height is

Total height = 129.37 m + 151.82 m

Total height = 281.19 m

7 0

3 years ago

How much does it cost to leave a porch light on all night?

worty [1.4K]

Cost = (0.001) x (the wattage of the light) x (the number of hours it's left on) x (the cost of each kilowatt-hour of electrical energy where you live).

6 0

2 years ago