Answer:
In what way is iron unique among the elements?
It has the lowest mass per nuclear particle.
Match words at the left to the correct blanks in the sentences on the right. Not all words will be used.
-The energy that drives the expansion of a star into a subgiant or red giant comes from HYDROGEN SHELL FUSION
-Stars with mass greater than about 8 solar masses are considered HIGH-MASS STARS
-The final stage of core fusion in a low-mass star is HELIUM FUSION
-Stars that are fusing hydrogen in their cores are MAIN-SEQUENCE STARS
-When it dies, a high-mass star explodes as a SUPERNOVA
-A star that is expanding (into a subgiant and then a giant) has a(n) INERT HELIUM CORE
-When it dies, a low-mass star expels a PLANETARY NEBULA
-Stars with masses less than about two solar masses are considered LOW-MASS STARS
Hi please may someone help me especially on the sketch part.
An object falls from a hovering helicopter and hits the ground at a speed of 30 m/s. How long does it take the object to reach the ground and how far does it fall? Sketch a velocity-time graph for the object (ignore air resistance).
Ignoring the air resistance it will take about 3 seconds for the object to reach the ground.We know that the acceleration due to gravity is 10m/s2.
We also know that the final velocity is 30 m/s while the initial velocity is 0 m/s
we can use the formulae for acceleration to calculate the time taken/
(final - initial velocity)/timetaken=10
(30-0)/timetaken=10
timetaken =30/10=3 seconds
If you have a 200g sample of a radioactive isotope that has a half life of 50 years, hc
much will you have left at the end of 200 years?
a. 12.5 g
b. 100 g
c. 50 g
d. 25 g
Answer:
The correct option is;
a. 12.5 g
Explanation:
The given parameters are;
The initial mass of the radioactive substance = 200 g
The half life of the radioactive substance = 50 years
The time duration for the disintegration = 200 years
The formula for half life is given as follows;
[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}}[/tex]
Where:
N(t) = Quantity of the remaining substance
N₀ = Initial radioactive substance quantity = 200 g
t = Time duration = 200 years
[tex]t_{1/2}[/tex] = Half life of the radioactive substance 50 years
Therefore, we have;
[tex]N(t) =200 \times \left (\dfrac{1}{2} \right )^{\dfrac{200}{50} } =200 \times \left (\dfrac{1}{2} \right )^4 = 12.5 \ g[/tex]
Therefore, at the end of 200 years, the quantity left = 12.5 g.
Question is on the picture. Answers: A. 0.1 J/g*C B. 0.2 J/g*C C. 0.4 J/g*C D. 4 J/g*C
Answer:
B. 0.2 J/g/°C
Explanation:
The solid phase is the first segment (from 0°C to 50°C).
q = mCΔT
200 J = (20 g) C (50°C)
C = 0.2 J/g/°C
What two factors determine how much potential energy an object has?
Answer:
The mass of the object and its height in the gravitational field of the Earth.
Explanation:
If we are talking about gravitational potential energy which is defined as:
[tex]U=m\,*\,g\,*\,h[/tex]
being "m" the object's mass, "g" the acceleration due to gravity, and "h" the height at which the object is located relative to the conventionally picked level for zero of potential energy.
As long as the value of "g" is constant, the only two variables that determine the gravitational potential energy are the mass (m) of the object and its relative height (h).
Answer:
The objects weight and height above Earth's surface
Explanation:
K12 :)
Question 1 (2 points)
(01.01 LC)
Which of the following is a characteristic of science? (2 points)
QU
Reproducible by other scientists
Ob
The personal opinion of the scientist
С
Using variable conditions for each test
d
Including only the data that supports a hypothesis
Answer:
Reproducible by other scientists
Explanation:
I just took the test
A machine can never be 100% efficient because some work is always lost due to which factor? friction gravity static input force
Explanation:
Hi,
The answer is friction.
There is almost no machine which are not affected by friction. It losts some work due to friction while working.
Hope it helps..
Answer:
friction
Explanation:
the other options dont effect efficiency
the unit of energy is a derived unit
Explanation:
Hi, there!!
Energy is defined as the capacity or ability to do work. It's SI unit is Joule.
here,
Joule = (kg×m×m)/(s×s)
= kg×m^2/s^2.
Therefore, the derived unit is kg.m^2 by s^2.
Hope it helps...
whats suface tension
Answer: "Surface tension is a film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area."
Hope this helps!
Answer:
Explanation:
Surface tension is the property of a liquid surface. It is an effect where the surface of the liquid is strong.
example - small insects can walk on water as they do not have enough weight to penetrate it.
This image might help you
Hope it helps
plz mark as brainliest!!!!!!!
An object accelerates to a velocity of 230 m/s over a time of 2.5 s. The acceleration it experienced was 42 m/s2. What was its initial velocity?
Answer:
230 = x + 105
x= 125
Explanation:
v = v0 + at
The ways to measure the mass and volume of irregular object
Answer:
When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.
The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.
One way to measure the volume of the object is using water... how we do it?
Get some recipient with water, measure the height of the water.
Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.
Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)
Jaiden is writing a report about the structure of the atom in her report,she says that the atom has three main parts and two subatomic particles. Do you agree with her?why or why not
Answer:
I do not agree with the answer.
Because in reality, the atom has 2 main parts and 3 subatomic particles.
Explanation:
The parts of an atom are:
- The crust: It is the outer part of the atom and is the place where the electrons are.
- The nucleus: It is the central part of the atom and is the place that contains the protons and neutrons.
The subatomic particles of the atom are:
- Electrons: They are negatively charged particles that go in the atom's crust and are divided into specific sections.
- Protons: They are particles with a positive electric charge, the number of protons in the nucleus of an atom is what determines the atomic number of an element.
- Neutrons: They are atoms with no electric charge.
I need help. can I get some
Explanation:
a) Acceleration is the slope of the velocity vs time graph. When velocity vs time is a straight line, that means the acceleration is a constant. F = ma, so the resultant force is also constant.
b) As air resistance increases, the acceleration begins to decrease.
c) A falling object stops accelerating when it reaches terminal velocity.
d) F = ma, so when the acceleration is 0, the resultant force is also 0.
The radius of a small ball is around 3.79747 cm. The radius of a basketball is about 3.16 times larger. What is the ratio of the surface areas of the small ball and a basketball? 2. What is the ratio of their volumes?
Explanation:
The ratio of the areas is the square of the ratio of the radii.
A/A = 3.16² = 9.99
The ratio of the volumes is the cube of the ratio of the radii.
V/V = 3.16³ = 31.6
i)Distinguish between different methods of charging. ii) You are provided with a positively charged gold leaf electroscope. State and explain what happens when a. a glass rod rubbed with silk is brought near the disc of electroscope. b. an ebonite rod rubbed with fur is brought near the disc of electroscope. c. an uncharged metal rod is brought near the disc of electroscope d. a glass rod rubbed with silk is rolled on the disc of electroscope.
Answer:
Explanation:
On rubbing a glass rod with silk, the electrons from the glass rod get transferred to the silk. The silk now has an excess of electrons and so is negatively-charged. On the other hand, the glass rod is deficient in electrons and hence is positively-charged.
In the above case, the silk undergoes negative electrification.
Now, when the positively charged glass rod is touched on the disc of a negatively charged gold leaf electroscope, the electrons shifts towards rod, hence amount of charge on gold leaves decreases and the divergence between the gold leaves decreases as unlike charges attract each other.
Hence, the divergence decreases when a glass rod rubbed with silk is brought near the disc of negatively charged electroscope.
hope it helps pls mark me as brainliest
Matter is anything that has mass and takes up
space.
Which of the following is an example of
matter?
A. ear phones
B. music
C. sunlight
D. heat
Answer: ear phones
Explanation:
You can physically hold ear phones, but you can't hold music, sunlight, or heat.
Which statement describes one feature of Rutherford's model of the atom?
O The atom is mostly empty space.
O The atom cannot be divided into smaller particles.
O Electron clouds are regions where electrons are likely to be found.
O The electrons are located within the positive material of the nucleus.
Answer:
The atom is mostly empty space.
Explanation:
Ernest Rutherford in the year 1911 developed a model of an atom. In his model the atom was shown that the atom is mostly empty spaces composed of negative electrons which orbits round a positive nucleus just like planets revolving round the sun.
Rutherford came up with this model by performing experiments in 1909 which involves the scattering of alpha particles on a thin gold foil. From this experiments he came up with his model.
Answer:
A!
Explanation:
The atom is mostly empty space.
A 1.00-kg glider attached to a spring with a force constant 25.0 N/m oscillates on a frictionless, horizontal air track. At t = 0, the glider is released from rest at x = -2.80 cm (that is, the spring is compressed by 2.80 cm). (a) Find the period of the glider's motion. How does the period depend on the mass and the spring constant? Does it depend on the amplitude of oscillation? s (b) Find the maximum values of its speed and acceleration. speed m/s acceleration m/s2 (c) Find the position, velocity, and acceleration as functions of time. (Where position is in m, velocity is in m/s, acceleration is in m/s2, and t is in s. Use the following as necessary: t.) x(t) = v(t) = a(t) =
Answer:
a) T = 1.26 s , b) v_max = 0.14 m / s , a_max = 0.7 m / s²
c) x = 0.028 cos (5 t) , v = - 0.14 sin 5t, a = - 0.7 cos 5t
Explanation:
This is a simple harmonic motion exercise that is described by the equation
x = A cos (wt +Ф)
with
w = √ (k / m)
let's apply this expression to our case
a) Angular velocity is related to frequency
w = 2π f
frequency and period are related
f = 1 / T
we substitute
2π / T = √ (k / m)
T = 2π √(m / k)
let's calculate
T = 2π √(1/25)
T = 1.26 s
In the expression for the period, the amplitude does not appear, therefore there is no dependence, as long as Hooke's law is fulfilled, which is correct for small amplitudes.
b) in the initial equation we have the position as a function of time, let's use the definition of speed and acceleration
v = dx / dt
v = - A w sin (wt + Ф)
the speed is maximum when the sine is -1
v_max = A w
w = √ (k / m)
w = √ 25/1
w = 5 rad / s
the amplitude of the movement is equal to the maximum compression of the spring
A = 2.8 cm = 0.028 m
we substitute
v_max = 0.028 5
v_max = 0.14 m / s
acceleration
a = dv / dt
a = - A w² cos (wt + Ф)
the acceleration is maximum when the cosine is -1
a_max = A w²
let's calculate
a_max = 0.028 5²
a_max = 0.7 m / s²
c) let's start by finding the phase constant
v = -A w cos (wt + Ф)
at t = 0 they indicate that the system has v = 0
0 = -A w sin (0 + Ф)
Ф = sin⁻¹ 0
Ф = 0
we write the equation
x = 0.028 cos (5 t)
v = - A w sin (wt + Ф)
v = - 0.028 5 sin (5t + 0)
v = - 0.14 sin 5t
acceleration
a = - A w² cos (wt + Ф)
a = - 0.028 5 2 cos (5 t + 0)
a = - 0.7 cos 5t