Answer:1m
Explanation:
2n=0.4m
5n=?
5n×0.4/2n=1m
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.
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.
The period of a pendulum is the time it takes the pendulum to swing back and forth once. If the only dimensional quantities that the period depends on are the acceleration of gravity, g, and the length of the pendulum, ℓ, what combination of g and ℓ must the period be proportional to? (Acceleration has SI units of m • s-2.)
Answer: √(L/g)
Explanation:
Here we only work with the units:
The unit of the period is units of time, so we have:
[T] = [s]
Now, the units of the length of the pendulum are units of distance:
[L] = [m]
And the units of the acceleration are:
[g] = [m/s^2]
Now, we want to work with those two in such way that the end result is only in seconds.
First, we can see that in g we have seconds square, so we know that we should use a square root.
Then we can divide L by g in order to remove the distance unit, and to have the time unit in the numerator
[L/g] = [m*s^2/m] = [s^2]
Now we apply the square root:
[√(L/g)] = [√s^2] = [s]
Then the combination is: √(L/g)
T = k*√(L/g)
where k is the constant of proportionality.
Astronomers were at first surprised to find complicated molecules in the interstellar medium. They thought ultra-violet light from stars would break apart such molecules. What protects the molecules we observe from being broken apart
Answer:
The dust present in the clouds.
Explanation:
The complicated composition molecules that can be found in space are generally associated with clouds of dust. The significant amount of dust in these clouds provides protection not only for these molecules, but for any body that makes up or is associated with dust clouds.
It is exactly this dust that protects the molecules against the action of ultraviolet rays.
An average family of four uses roughly 1200 Liters of water per day (1L. - 1000 cm3). A lake that covers 50 km² with a uniform depth and
supplies water to a local town with a population of 40,000 people would lose depth every year due to water consumption form
the locals, Ignore evaporation, rain, creeks and rivers.
Answer:
#_total = 4.38 10⁹ liter
Explanation:
For this exercise we can use a direct proportion rule (rule of three). If 4 people use 1200 liters how much water 1 person consumes
#_water = 1 person (1200 liter / 4 person)
#water = 300 liters
Now we look for the consumption of this person in a year, if 1 person consumes 300 liters 1 day, how many liters they consume in a year (365 days)
#_water_person_total = 365 days (300 liters / 1 day)
#_water_person_total = 109500 liters
This is the water consumption of 1 person in a year, the total of 40000 people how much they consume
#_total = 40000 person (109500 liter / 1 person)
#_total = 4.38 10⁹ liter
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
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
What is CGS unit of weight
Answer:
[tex] \boxed{dyne}[/tex]Explanation:
The weight of a body is defined as the force with which it is attracted towards the centre of a planet. A spring balance measures it. It's unit is Newton ( N ) in the SI system and dyne in the CGS system.
Hope I helped!
Best regards!
Weight is force.
The CGS unit of force is the dyne.
The SI unit of force is the Newton.
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.)
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
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
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if you ran 15 km/hr for 2.5 hours, how much distance would you cover?
Answer: 37.5 km
Explanation:
The question is that
If you ran 15 km/hr for 2.5 hours, how much distance would you cover ?
Where
Speed = 15 km/ hr
Time = 2.5 hours
Using the formula for speed.
Speed = distance/time
Substitute speed and time into the formula
15 = distance/ 2.5
Make distance the subject of formula by cross multiplying.
Distance = 15 × 2.5
Distance = 37.5 km.
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
what is acceleration produced by a force of 12 newton exerted on an object of mass 3kg
Answer:
a=F/m
a=12N/3kg (here newton can be written as kgm/s^2 so kg will be cancelled)
a=4m/s^2
Explanation:
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.
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
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
Which of the following best describes a consumer?
0. a business owner who sells clothes
0. someone who studies economics
O. a farmer who sells his crops
O. a person who buys goods and services
Answer:
a business who buys goods and services
The particles of a GAS within a closed container will collide with the container walls, exerting a FORCE. The force per unit of AREA is known as what?
Answer:
Pressure
Explanation:
One of the theories propounded by the Kinetic molecular theory, and which also provides an explanation of the several gas laws, is the statement that the gas molecules in a container, travel in straight lines and are in constant collision with themselves and the walls of the container, thus exerting force. This force is the pressure which is defined as the force per unit area.
There is no loss of energy in the collisions involving the gas molecules and that is why their movement can be described as elastic. The descriptions of the behavior of gas molecules in the Kinetic Molecular Theory, give rise to Charles law, Boyle's Law, Avogadro's Laws, Dalton's Law, and Amonton's Law.
Answer:
The pressure
Explanation:
Molecules of gases are constantly in motion, colliding with the walls of their container. This constant collision impacts force on the walls of the container, which depends on the speed with which the molecules are moving. The speed with which these molecules travel depends on the average kinetic energy of the molecules, which is proportional to the temperature.
This force when exerted per unit area is the pressure the gases exert on the walls of the container.
Question 2 of 10
Which of the following is an Sl unit?
A. Foot
B. Inch
C. Meter
D. Mile
SUBMIT
Answer:
C. Meter
Explanation:
The International System of Unit (SI) is gotten from the french word Systeme international is a modern form of metric measurement. It is the system of measurement that is universally accepted. It is from this SI units that all other system of units are derived. There are seven basic SI units which are:
1) Length in Meter (m)
2) Time in Seconds (s)
3) Amount of Substance in mole (m)
4) Electric current in ampere (A)
5) Temperature in kelvin (k)
6) Luminous intensity in candela (cd)
7) Mass in kilogram (kg)
A physical inventory on December 31 shows 3500 units on hand. Bonita sells the units for $15 each. The company has an effective tax rate of 20%. Bonita uses the periodic inventory method. The weighted-average cost per unit is
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
Match words at the left to the correct blanks in the sentences on the right. Not all words will be used.1. The energy that drives the expansion of a star into a subgiant or red giant comes from HYDROGEN SHELL FUSION2. Stars with mass greater than about 8 solar masses are considered HIGH-MASS STARS3. The final stage of core fusion in a low-mass star is HELIUM FUSION4. Stars that are fusing hydrogen in their cores are MAIN-SEQUENCE STARS5. When it dies, a high-mass star explodes as a SUPERNOVA6. A star that is expanding (into a subgiant and then a giant) has a(n) INERT HELIUM CORE7. When it dies, a low-mass star expels a PLANETARY NEBULA8. Stars with masses less than about two solar masses are considered LOW-MASS STARS
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
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.
an object is +2 m from the reference point. the object starts from rest it travels for 3 seconds and has a final position of -16 m. what is the acceleration of the object?
Answer:
Solution
Given:
initial velocity (u)=0m/s (because an object
starts from the rest)
time (t)=3sec
diatance travelled(s)=14m(16-2=14)
acceleration (a)=?
Now,
According to the formula
s=ut+1/2at^2
or,14 =0×3+1/2×a×3^2
or, 14=0+a/2×9
or, 14=9a/2
or, 9a=28
or, a=28/9
or, a=3.1 m/s^2
Therefore, the acceleration of the object is 3.1m/s^2 ans.
Please help me ASAP...
A train increases its speed steadily from 10 m/s to 20 m/s in 1 minute.
a What is its average speed during this time, in m/s?
b How far does it travel while increasing its speed?
Answer:
A: 15 m/s
B: 900 Meters
Explanation:
A. Average speed is equal to final velocity plus initial velocity divided by two
Va= (20+10)/2 = 15 m/s
B.
distance = speed × time
D= 15 m/s * 60s = 900 Meters
Answer:
Answer is in the attachment.
Explanation:
Hope this helps.
Please mark me as Brainliest.
within a conventional light bulb, which of the following would not be considered a state of matter
a. the glass shell of the bulb
b. the metal base of the bulb
c. the air inside the bulb
d. the light from the bulb
Answer:
D
Explanation:
because light has no space nor mass
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 :)
i) A 100 W and 60 W bulb are joined in series and connected to the mains. Which bulb
will glow brighter? Why?
ii) A 100 W and a 60 W bulb are joined in parallel to the mains. Which bulb will
glow brighter? Why?
Answer:
i) 60 W
ii) 100 W
Explanation:
In each case, the bulb that dissipates the most power is the bulb that glows brighter. Power is voltage times current (P = VI). Using Ohm's law, we can rewrite this as P = I²R or P = V²/R.
Bulbs are rated at a certain power for a certain voltage. P = V²/R, so the bulb with the lower resistance will have the higher power rating. Therefore, the 100 W bulb has a lower resistance than the 60 W bulb.
i) They are in series, so they have the same current. P = I²R, so the bulb with the higher resistance will glow brighter. That's the 60 W bulb.
ii) They are in parallel, so they have the same voltage. P = V²/R, so the bulb with the lower resistance will glow brighter. That's the 100 W bulb.
answer answer answer it it it
Answer:
Parachutes
Explanation:
Your parachute allows you to descend more slowly because it lowers terminal velocity by increasing your air resistance. Most parachutes are designed to create a large amount of drag and allow you to land at a safe, low speed.
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