What is sieving? Give an example where this method is used. (2)
Answer:
sieving is when you separate particles of different sizes.
Explanation:
separating sand mixtures
separating chaffs from local garri
Andrea, a 61.5 kg sprinter, starts a race with an acceleration of 3.700 m/s2. If she accelerates at that rate for 12.00 m and then maintains that velocity for the remainder of a 100.00 m dash, what will her time (in s) be for the race
Answer:
The total time it will take her to complete the race is 13.17 s
Explanation:
Given;
mass of the sprinter, m = 61.5 kg
acceleration of the sprinter, a = 3.7 m/s²
first distance covered, d₁ = 12 m
Determine her velocity for the first 12 m;
v² = u² + 2as
v² = 0 + (2 x 3.7 x 12)
v² = 88.8
v = √88.8
v = 9.42 m/s
Determine her time for the first 12 m;
v = u + at
9.42 = 0 + 3.7t₁
9.42 = 3.7t₁
t₁ = 9.42 / 3.7
t₁ = 2.55 s
Determine the time it will take her to complete the last 100 m at a constant velocity of 9.42 m/s
s = vt₂ + ¹/₂at₂²
s = vt₂ + ¹/₂(0)t₂²
s = vt₂
100 = 9.42t₂
t₂ = 100 / 9.42
t₂ = 10.62 s
The total time it will take her to complete the race = 2.55 s + 10.62 s
= 13.17 s
PLS HELP ME. A 0.0780 kg lemming runs off a 5.36m high cliff at 4.84 m/s what is it potential energy when it lands?
Answer:
p.e=0.078kg×1/2×5.36m
p.e=0.913j
A set of charged plates is separated by 8.08*1^-5 m. When 2.24*10^-9 C of charge is placed on the plates, it creates a potential difference of 855 V. What is the area of the plates
q=CV
q=(ϵ0×A)/(d)×(V)
(2.24×10^−9)=((8.08×10^−4)(8.85×10−12))/(d)× (855)
d=2.7294×10^-3
Dr. John Paul Stapp was a U.S. Air Force officer who studied the effects of extreme deceleration on the human body. On December 10, 1954, Stapp rode a rocket sled, accelerating from rest to a top speed of 282 m/s (1015 km/h) in 5.00 s, and was brought jarringly back to rest in only 1.40 s. Calculate his:
a. acceleration in his direction of motion
b. acceleration opposite to his direction of motion.
Answer: [tex]56.4\ m/s^2, 201.42\ m/s^2[/tex]
Explanation:
Given
Rocket attain a velocity of [tex]v=282\ m/s[/tex] in a time period of [tex]t=5\ s[/tex]
It was brought jarringly back to rest in only [tex]t'=1.4\ s[/tex]
Acceleration is the change in velocity of the object over a period of time
(a) Acceleration in his direction of motion
[tex]\Rightarrow a=\dfrac{v-0}{t}\\\\\Rightarrow a=\dfrac{282}{5}\\\\\Rightarrow a=56.4\ m/s^2[/tex]
(b) acceleration opposite to his direction of motion i.e. deceleration is
[tex]\Rightarrow a_d=\dfrac{0-v}{t'}\\\\\Rightarrow a_d=\dfrac{-282}{1.4}\\\\\Rightarrow a_d=-201.42 \ m/s^2\\\Rightarrow a_d=201.42\ \text{decelration}[/tex]
Select the statement that is true:
A. Food chains and food webs have nothing to do with each other.
B. A food web and a food chain are different names for the same thing.
C. A food chain is a part of a food web.
D. A food web is part of a food chain.
Answer:
C
Explanation:
A food chain outlines who eats whom. A food web is all of the food chains in an ecosystem.
Answer:
C
Hope this helped :D
what is a crystal as applied in physics
Answer:
The correct answer is - A matter that has an ordered arrangement of atoms, molecules, or ions.
Explanation:
In physics, a crystal is a type of solid matter in which a highly arranged molecule or atoms present to form a lattice that extended in all directions. It is a lightweight clear solid which is normally is colorless.
It can be cubic, hexagonal, triclinic, monoclinic, orthorhombic, tetragonal, and trigonal that are ordered arrangments. Its internal symmetry is visible to its surface.
The human eye has two lenses.
O true
O False
Answer:
true its truedjjs sjsnsns
A box attached to a spring is being pulled across a flat frictionless surface. The spring constant is 45 N/m, the box is accelerating at
1.3 m/s2, and the spring is stretched by 0.88 m. What is the mass of the box?
26 kg
O 38 kg
30 kg
O 33 kg
Plzzzzz help
Answer:
Mass = 30.46 kg
Explanation:
Given the following data;
Spring constant = 45 N/m
Acceleration = 1.3 m/s²
Extension = 0.88 m
To find the mass of the box;
First of all, we would determine the force acting on the spring.
Force = spring constant * extension
Force = 45 * 0.88
Force = 39.6 N
Next, we find the mass using Newton's second equation of motion.
Force = mass * acceleration
39.6 = mass * 1.3
Mass = 39.6/1.3
Mass = 30.46 kg
A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 19.0 m/s when the hand is 2.50 m above the ground.
Required:
How long is the ball in the air before it hits the ground?
Answer: 4 s
Explanation:
Given
The ball leaves the hand of student with a speed of [tex]u=19\ m/s[/tex]
When the hand is [tex]h=2.5\ m[/tex] above the ground
Using the equation of motion we can write
[tex]h=ut+\dfrac{1}{2}at^2[/tex]
Substitute the values
[tex]\Rightarrow 2.5=-19t+0.5\times 9.8t^2\\\Rightarrow 4.9t^2-19t-2.5=0\\\\\Rightarrow t=\dfrac{19\pm \sqrt{(-19)^2-4\times 4.9\times (-2.5)}}{2\times 19}\\\Rightarrow t=4.0049\quad [\text{Neglecting the negative value of }t][/tex]
Thus, the ball will take 4 s to hit the ground.
The quantum mechanical model of the hydrogen atom requires that if the orbital quantum number of the hydrogen atom is 4, there will be how many permitted orbital magnetic quantum numbers will be:_______
Answer:
-4, -3, -2, -1, 0, 1, 2, 3, 4
Explanation:
There are four sets of quantum numbers;
1) principal quantum number (n)
2)orbital quantum number (l)
3) magnetic quantum number (ml)
4) Spin quantum number (s)
These quantum numbers describes the probability of finding the electron within the atom.
The values of the magnetic quantum number depends on the orbital quantum number. The range of values of the magnetic quantum number is -l to +l
Hence, if the orbital quantum number of the hydrogen atom is 4, the permitted orbital magnetic quantum numbers will be; -4, -3, -2, -1, 0, 1, 2, 3, 4.
WILL REWARD BRAINLIEST
A thermonuclear fusion reaction cannot be maintained in the oceans of Earth because
A)the deuterium in the ocean is not radioactive.
B)the density is not high enough.
C) there is insufficient deuterium in the ocean.
D)the temperature is not high enough.
Answer: D) the temperature is not high enough.
Explanation:
The nuclear fusion reactions involve the fusion of the nucleus of the heavy metals. This is done in a nuclear reactor and energy is produced in the heat energy along with radiations. This system requires heat energy for the accomplishment of the nuclear reactions. The temperature of the system cannot be maintained inside the ocean so nuclear fusion will not occur in the ocean.
Probability of a woman wearing green to walk into a restaurant
Iron is a solid phase of iron still unknown to science. The only difference between it and ordinary iron is that Iron forms a crystal with an fcc unit cell and a lattice constant . Calculate the density of Iron.
The question is incomplete. The complete question is :
Iron β is a solid phase of iron still unknown to science. The only difference between it and ordinary iron is that Iron β forms a crystal with an fcc unit cell and a lattice constant, a = 0.352 nm. Calculate the density of Iron β.
Solution :
The density is given by :
[tex]$\rho = \frac{ZM}{a^3N_0} \ \ g/cm^3$[/tex] ..................(i)
Here, Z = number of atoms in a unit cell
M = atomic mass
[tex]$N_0$[/tex] = Avogadro's number = [tex]$6.022 \times 10^{23}$[/tex]
a = edge length or the lattice constant
Now for FCC lattice, the number of atoms in a unit cell is 4.
So, Z = 4
Atomic mass of iron, M = 55.84 g/ mole
Given a = 0.352 nm = [tex]$3.52 \times 10^{-8}$[/tex] cm
From (i),
[tex]$\rho = \frac{ZM}{a^3N_0} $[/tex]
[tex]$\rho = \frac{4 \times 55.84}{(3.52 \times 10^{-8})^3 \times 6.022 \times 10^{23}} $[/tex]
[tex]$= 8.51 \ \ g \ cm ^{-3}$[/tex]
Therefore, the density of Iron β is [tex]$ 8.51 \ \ g \ cm ^{-3}$[/tex].
A 615 N student standing on a scale in an elevator notices that the scale reads 645 N. From this information, the student knows that the elevator must be moving Group of answer choices You cannot tell if it is moving upward or downward. upward. downward.
Answer:
The elevator must be moving upward.
Explanation:
During the motion of an elevator, the weight of the person deviates from his or her actual weight. This temporary weight during the motion is referred to as "Apparent Weight". So, when the elevator is moving downward, the apparent weight of the person becomes less than his or her actual weight.
On the other hand, for the upward motion of the elevator, the apparent weight of the person becomes more than the actual weight of that person.
Since the apparent weight (645 N) of the student, in this case, is greater than the actual weight (615 N) of the student.
Therefore, the elevator must be moving upward.
A Van de Graaff generator is one of the original particle accelerators and can be used to accelerate charged particles like protons or electrons. You may have seen it used to make human hair stand on end or produce large sparks. One application of the Van de Graaff generator is to create x-rays by bombarding a hard metal target with the beam. Consider a beam of protons at 1.85 keV and a current of 5.40 mA produced by the generator. (a) What is the speed of the protons (in m/s)
Answer:
The speed of the proton is [tex]v =5.95\times 10^{5} m/s[/tex]
Explanation:
Energy, E = 1.85 keV
mass of proton, m = 1.67 x 10^-27 kg
Let the speed is v.
The kinetic energy is given by
[tex]K = 0.5m\times v^{2}\\\\1.85\times \1.6\times 10^{-16} = 0.5\times 1.67\times 10^{-27}\times v^{2}\\\\v =5.95\times 10^{5} m/s[/tex]
15. In the diagram shown, the emf of the secondary winding is______ the emf of the primary winding.
A. Less than
B. Equal to
C. Greater than
Answer:
Greater than
Explanation:
A voltage of 75 V is placed across a 150 Ω resistor. What is the current through the resistor?
Answer:
0.5 A
Explanation:
Applying,
V = IR.................. Equation 1
Where V = Voltage, I = current, R = Resistance.
make I the subject of the equation
I = V/R............... Equation 2
From the question,
Given: V = 75 V, R = 150 Ω
Substitute these values into equation 2
I = 75/150
I = 0.5 A.
Hence the cuurent through the resistor is 0.5 A
A metallic circular plate with radius r is fixed to a tabletop. An identical circular plate supported from above by a cable is fixed in place a distance d above the first plate. Assume that d is much smaller than r. The two plates are attached by wires to a battery that supplies voltage V.
Required:
a. What is the tension in the cable?
b. Compute the energy stored in the electric field after the top plate was raised.
Answer:
A) F = V²E_o•πr²/2d²
B) U = E_o•Aπr²V²/2d
Explanation:
A) Since we have two circular plates, the formula for the electric field is expressed as;
E = V/d
Where;
V is voltage
d is distance
However, the net electric field produced is given by;
E' = V/2d
The tension in the cable can then be expressed as;
F = qE'
Where q is charge
Thus;
F = qV/2d - - - (eq 1)
We also know that;
C = q/V = E_o•A/d
A is area = πr²
Thus;
q/V = E_o•πr²/d
q = VE_o•πr²/d
Let's put VE_o•πr²/d for q in eq 1 to get;
F = V²E_o•πr²/2d²
B) formula for the energy stored in the electric field is;
U = ½CV²
From earlier, we saw that; C = E_o•A/d
Thus;
U = ½E_o•AV²/d
A = πr²
Thus;
U = E_o•Aπr²V²/2d
If by some miracle you were able to run electrical appliances with the energy you obtained from food (maybe something like running on a human hamster wheel) how many pieces of pizza (at 300 Calories each) would you have to eat to watch the Super Bowl (4 hours long) on your HDTV (175 Watts)? Assuming an efficiency of 20% for the human body, your electrical energy output is only 20% of your caloric energy intake.
Answer:
1.00 × 10⁴ pieces of pizza
Explanation:
Step 1: Calculate the energy needed to watch the Super Bowl.
We need to produce energy to make an HDTV work (175 W) for 4 hours. First, we will convert, 4 hours to seconds using the conversion factor 1 h = 3600 s.
4 h × 3600 s/1 h = 14400 s
The energy required is:
14400 s × 175 J/s = 2.52 × 10⁶ J
We can convert this to calories using the conversion factor 1 cal = 4.184 J.
2.52 × 10⁶ J × 1 cal/4.184 J = 6.02 × 10⁵ cal
Step 2: Calculate the calories that the person should consume
Assuming an efficiency of 20% for the human body, the calories that a person should consume are:
6.02 × 10⁵ cal × 100/20 = 3.01 × 10⁶ cal
Step 3: Calculate the number of pieces of pizza to be consumed
Each piece of pizza contains 300 cal.
3.01 × 10⁶ cal × 1 piece/300 cal = 1.00 × 10⁴ pieces
what do you know about Russia?
Answer:
Russia is the largest country in the world covering more than 6.6 million square miles. ... Russia also spreads across two continents, covering a portion of Eastern Europe that borders the Ural Mountains. 4. The country's official name is the Russian Federation.
Answer:
10 Things to Know About Russia
The world's largest country has the longest railway, second-largest art museum in the world and is home to many billionaires.
Russia is the world's largest nation with a rich history and several dozen ethnic groups. Its history is dominated by invasions, monarchies and a the authoritarian 20th-century Soviet regime. Its current politicians are often at odds with Western values and clash with both Europe and the United States.
Here are 10 interesting facts about Russia.
1. Russia is the largest country in the world covering more than 6.6 million square miles.
2. It is located in the Northern Hemisphere and borders two oceans -- the Arctic Ocean and the North Pacific Ocean.
3. Russia also spreads across two continents, covering a portion of Eastern Europe that borders the Ural Mountains.
4. The country's official name is the Russian Federation.
5. The median age for Russia's population is 39.6 years old. There are about 140 million residents in the country as of 2017.
6. Russia's capital city Moscow is one of the wealthiest cities in the world by the number of billionaires. In 2018, the city reported 69 billionaires, after New York, Hong Kong and San Francisco.
7. Also in Moscow there is a restaurant staffed only with twins, called the Twin Stars.
8. The second-largest art museum in the world, the Hermitage, is located in Russia's former capital, Saint Petersburg. The museum has more than 3 million art pieces.
9. The deepest lake in the world (deeper than 5,000 feet), Lake Baikal, is located in Siberia.
10. The best known train route in Russia is the Trans-Siberian railway, the world's longest railway, connecting Moscow to Vladivostok. Yet there are several other scenic train routes that connect the capital to Beijing via Mongolia or Manchuria.
A force (5ỉ - ;)N moves an object from the point P (1,3) m to the point Q (3, 8) m.
The work (in )) done by the force is
Select one:
a. -10
O b.5
o c.-13
d. 8
Answer:
b) 5 J
Explanation:
Work is the energy transferred by an object when acted by a force along a displacement. Work is the product of force and displacement. The SI unit of work is the joules (J)
To calculate the work done by the force, we have to first get the displacement (D) of the object. Hence:
Displacement (D) = Q(3, 8) - P(1, 3) = (3 - 1, 8 - 3) = (2, 5) = 2i + 5j
The work done is the dot product of the force and the displacement. Force = 5i - j. Hence:
Work done = (5i - j)(2i + 5j) = 10 - 5 = 5 J
A red apple reflects ______
light and absorbs all other
colours.
A red apple reflects Red light and absorbs all other colours.
A cylindrical tank has a tight-fitting piston that allows the volume of the tank to be changed. The tank originally contains air with a volume of 0.175 m^3 at a pressure of 0.350 atm. The piston is slowly pulled out until the volume of the gas is increased to 0.365 m^3.
Required:
If the temperature remains constant, what is the final value of the pressure?
Answer:
the value of the final pressure is 0.168 atm
Explanation:
Given the data in the question;
Let p₁ be initial pressure, v₁ be initial volume.
After expansion, p₂ is final pressure and v₂ is final volume.
So using the following equations;
p₁v₁ = nRT
p₂v₂ = nRT
hence, p₁v₁ = p₂v₂
we find p₂
p₂ = p₁v₁ / v₂
given that; initial volume v₁ = 0.175 m³, Initial pressure p₁ = 0.350 atm,
final volume v₂ = 0.365 m³
we substitute
p₂ = ( 0.350 atm × 0.175 m³ ) / 0.365 m³
p₂ = 0.06125 atm-m³ / 0.365 m³
p₂ = 0.168 atm
Therefore, the value of the final pressure is 0.168 atm
help me with following question.
Answer:
The answer for this question is 50k N.m
How much time does it take for an eagle flying at a speed of 50 kilometers per hour to travel a distance of 2000 kilometers?
Answer:40 hour
Explanation:
Una partícula alfa (la cual es un núcleo del átomo de helio) se mueve hacia el norte con una velocidad de 3.8 X 10^5 m/s en una región donde el campo magnético es 1.9 T y está apuntando horizontalmente hacia el este. ¿Cuál es la magnitud y la dirección de la fuerza magnética sobre esta partícula alfa?
Answer:
F = 23.1 10⁻¹⁴ N, points inside the page
Explanation:
The magnetic force is given by the expression
F = q v x B
bold letters indicate vectors, the magnitude of this formula is
F = q v B sin θ
in this case the magnetic field is in the east direction and the particle moves north, so the angle is 90 and the sine 90 = 1
F = q v B
F = 2 1.6 10⁻¹⁹ 3.8 10⁵ 1.9
F = 23.1 10⁻¹⁴ N
the direction of the force is given by the right hand rule, for a positive charge
the thumb points in the directional of the speed, in this case towards the North
the other fingers extended in the direction of the magnetic field, in this case to the East
the palm points in the direction of the force, consequently it points inside the page,
What is the definition of power.
Answer:
What is the definition of power.
Explanation:
ability to do or act; capability of doing or accomplishing something.
Answer:
Hey buddy you are in college and I am in 8th standard so, There must be a difference between your level and mine. (:
Explanation:
Power is energy to exert force on objects, machinery use etc.
Sorry if not helpful ):
Given this relationship, if you and your twin sibling (assuming you have the same mass) were to be separated by three times your original distance, what is the new gravitational force between you?
Answer:
The new force becomes (1/9)th of the original force.
Explanation:
The gravitational force between two masses is given by :
[tex]F=G\dfrac{m_1m_2}{r^2}[/tex]
Where
r is the distance between masses,
If the new distance is, r' = 3r
The new force is given by :
[tex]F'=G\dfrac{m_1m_2}{r'^2}\\\\F'=G\dfrac{m_1m_2}{(3r)^2}\\\\F'=\dfrac{1}{9}\times G\dfrac{m_1m_2}{r^2}\\\\F'=\dfrac{F}{9}[/tex]
So, the new force becomes (1/9)th of the original force.
Suppose we have a spaceship about the size of a typical ocean cruise ship today, which means it has a mass of about 120 million kilograms, and we want to accelerate the ship to a speed of 12 % of the speed of light. Suppose you want to generate the energy to get it to cruising speed using matter-antimatter annihilation.
Part A. How much energy would be required? (Hint: You can find the answer simply by calculating the kinetic energy of the ship when it reaches its cruising speed; because 12 % of the speed of light is still small compared to the speed of light, you can use the formula that tell us that kinetic energy = 12mv2.) Express your answer using two significant figures.
Part B. How does your answer compare to total world energy use at present, which is about 5×1022 joules per year? How does your answer compare to total world energy use at present, which is about joules per year? EspaceshipEworldenergyuse∼1 EspaceshipEworldenergyuse∼105 EspaceshipEworldenergyuse∼1020
Part C. The typical cost of energy today is roughly 5¢ per 1 million joules. Using this price, how much would it cost to generate the energy needed by this spaceship? Express your answer using two significant figures.
Answer: A 7.8 ·10^22 J B 1.6 times C 3.9 ·10^15 $
Explanation: A : Speed of light c = 3.0·10^8 m/s, 0.12·c = 3.6·10^7 m/s
Mass is 120·10^6 kg . Change of kinetic energy
E = ½mv² = 0.5 · 120·10^6 kg · (3.6·10^7 m/s)² = 7.776·10^22 J
B exponent is same , 7.776 / 5 = 1,55 times of energy use of Earth in year.
C Energy is 7.776·10^22 J / 10^6 = 7.776·10^16 MJ
Price is 0.05 $ · 7.776·10^16 MJ = 3.888·10^15 $
A. The energy required to get to the cruising speed is 7.8×10²² J
B. The energy needed will be 1.56 times the total world energy
C. The cost price required to generate the energy needed by the spaceship is $ 3.9×10⁵
A. Determination of the energy
Mass (m) = 120×10⁶ Kg
Velocity of light = 3×10⁸ m/s
Velocity of spaceship = 0.12 × 3×10⁸ = 3.6×10⁷ m/s
Energy (E) =?E = ½mv²
E = ½ × 120×10⁶ × (3.6×10⁷)²
E = 7.8×10²² JThus, the energy needed is 7.8×10²² J
B. Comparing the energy needed to the total world energy.
Energy needed = 7.8×10²² J
World energy = 5×10²² J
Energy needed / World energy = 7.8×10²² / 5×10²²
Energy needed / World energy = 1.56
Cross multiply
Energy needed = 1.56 × World energyThus, the energy needed is 1.56 times the World energy
C. Determination of the cost required to generate the energy
1×10⁶ J = $ 0.05
Therefore,
7.8×10²² J = (7.8×10²² × 0.05) / 1×10⁶
7.8×10²² J = $ 3.9×10⁵
Therefore, the cost required to generate the energy is $ 3.9×10⁵
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