Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :
[tex]V = \dfrac{4 \pi r^3}{3}\\\\V = \dfrac{4\times 3.14 \times 0.5^3}{3}\ mm^3\\\\V = 0.523\ mm^3[/tex]
Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :
[tex]n = 520000\times 0.523\ grains\\\\n = 271960\ grains[/tex]
Electron cloud configuration for
Answer:
electrons are located around the nucleus of an atom.
Explanation:
Electron configurations describe where electrons are located around the nucleus of an atom. For example, the electron configuration of lithium, 1s²2s¹, tells us that lithium has two electrons in the 1s subshell and one electron in the 2s subshell.
Match the choices to the appropriate blank . Use each choice only once.
1. about 100,000 light-years
2. about 5 AU
3. about 8 light-years
4. about 1.5 AU
5. less than 0.01 AU
a. Mars is_____from the Sun.
b. Jupiter is_____from the Sun.
c. The star Sirius is_____from the Sun.
d. The diameter of the Milky Way Galaxy is_____.
e. The distance from Earth to the Moon is_____.
Answer:
1. about 1.5 AU
2. about 5 AU
3. about 8 light-years
4. about 100,000 light-years
5. less than 0.01 AU
Explanation:
a. Mars is about 1.5 AU from the Sun.
b. Jupiter is about 5 AU from the Sun.
c. The star Sirius is about 8 light-years from the Sun.
d. The diameter of the Milky Way Galaxy is about 100,000 light-years.
e. The distance from Earth to the Moon is less than 0.01 AU.
Note: AU is an acronym for Astronomical Unit and it is a standard unit by astronomers to illustrate the distance between the planetary bodies found in the solar system.
A 30 kg male emperor penguin under a clear sky in the Antarctic winter loses very little heat to the environment by convection; its feathers provide very good insulation. It does lose some heat through its feet to the ice, and some heat due to evaporation as it breathes; the combined power is about 12 W. The outside of the penguin's body is a chilly −22∘C, but its surroundings are an even chillier −38∘C. The penguin's surface area is 0.56 m2, and its emissivity is 0.97. What is the rate of energy loss by radiation
Answer:
Rate of energy loss by radiation is 28.31 Watt
Explanation:
Given that;
m = 30 kg
power p = 12 W
emissivity e = 0.97
Surface Area A = 0.56 m²
outside of the penguin's body T = −22°C
surroundings Temperature Ts = -38°C
the rate of energy loss by radiation = ?
Now, using Stefan-Boltzmann law;
P = σeA [ T⁴ - Ts⁴ ]
Stefan's constant σ = 5.67 × 10⁻⁸
so we substitute
P = 5.67 × 10⁻⁸ × 0.97 × 0.56 [ (-22 + 273 k)⁴ - (-38 + 273 k )⁴]
= 3.079944 × 10⁻⁸ [ 919325376]
= 28.31 Watt
the rate of energy loss by radiation is 28.31 Watt
Two boxes on opposite ends of a massless board that is 3.0 m long. The board is supported in the middle by a fulcrum. The box on the left has a mass (m1) of 25 kg, and the box on the right has a mass (m2) of 15kg. How far should the fulcrum be positioned from the left side of the board in order to balance the masses horizontally?
a. 0.38 m
b. 1.1 m
c. 0.60 m
d. 1.9 m
Answer:
b. 1.1 m
Explanation:
It is given that the total distance between the masses is equal to the length of the board, which is 3 m. Therefore,
[tex]s_{1} + s_{2} = 3\ m\\\\s_{2} = 3\ m - s_{1}\ --------- eqn(1)[/tex]
where,
s₁ = distance of fulcrum from left mass
s₂ = distance of fulcrum from right mass
In order to achieve balance, the torque due to both masses must be equal:
[tex]T_{1} = T_{2}\\m_{1}s_{1} = m_{2}s_{2}\\(25\ kg)(s_{1}) = (15\ kg)(s_{2})\\\\\frac{15\ kg}{25\ kg}(s_{2}) = s_{1}\\\\using\ eqn(1):\\(0.6)(3\ m - s_{1}) = s_{1}\\1.8\ m = 1.6\ s_{1}\\s_{1} = \frac{1.8\ m}{1.6}[/tex]
s₁ = 1.1 m
Hence, the correct option is:
b. 1.1 m
A researcher who does not want to manipulate or interfere with the behavior of research subjects would conduct a __________ study.
A.
cross-sectional
B.
naturalistic observation
C.
case
D.
longitudinal
Please select the best answer from the choices provided
A
B
C
D
Answer:
b
Explanation:
A researcher who does not want to manipulate or interfere with the behavior of research subjects would conduct a Naturalistic observation study.
What is observational research?Observational technique in the research field is usually, " watching something attentively in a scientific manner". If we are observing research technique and its phenomena naturally it's our interest to see in our own subjects. The subject will be known only when we observe the things. It's all about understanding, analyzing, predicting and manufacturing in a unique manner.
The types of observation techniques are:
Naturalistic observation.Participant observation.Structured observation.Naturalistic observation:
This is the observation which can be observed naturally and the phenomenon will be interacted only with the researchers not with the participants.
Some of the observational research methods are:
Thematic analysisGrounded theoryHence, Option B is the correct answer.
Learn more about the Naturalistic observation,
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what would happen to the surface temperature on Earth if large amounts of carbon dioxide were removed from the atmosphere?
Answer:
If carbon emissions stopped, the oceans catch up with the atmosphere, the Earth's temperature would rise about another 1.1F (0.6C).
Explanation:
which phenomenon supports the particular model of light?
Answer:
photoelectric effect
Explanation:
The photoelectric effect supports a particle theory of light in that it behaves like an elastic collision (one that conserves mechanical energy) between two particles, the photon of light and the electron of the metal.
What is displacement?
a. The distance an object travels.
b. The distance between the starting point and the ending point of an object's
journey.
C. The amount of time it takes an object to travel to a destination.
d. The path in which an object travels.
Answer:
displacement is the distance between the starting point and the ending point of an object's journey
A roller coaster rider traveling in a straight line changes from a speed of 4 m/s to 16 m/s in 3 seconds. What is the acceleration of the rider?
A. 1.33 m/s2
B. 3 m/s2
C. 5.33 m/s2
D. 4 m/s2
Answer:27
Explanation:
If a roller coaster rider traveling in a straight line changes from a speed of 4 m/s to 16 m/s in 3 seconds, then the acceleration of the rider would be 4 m / s² , therefore the correct answer is option D.
What are the three equations of motion?There are three equations of motion given by Newton,
v = u + at
S = ut + 1/2 × a × t²
v² - u² = 2 × a × s
As given in the problem, A roller coaster rider traveling in a straight line changes from a speed of 4 m/s to 16 m/s in 3 seconds.
By using the first equation of the motion,
v = u + at
16 = 4 + 3a
a = 16 -4 / 3
= 12 / 3
= 4 m / s²
Thus, the acceleration of the rider would be 4 m / s².
Learn more about equations of motion here, refer to the link given below ;
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What is the sum of internal energy
Your friend, a world-class long jumper, is trapped on the roof of a burning building. His only escape route is to jump to the roof of the next building. Fortunately for him, he is in telephone contact with you, a Physics 131 student, for advice on how to proceed. He has two options. He can jump to the next building by using the long-jump technique where he jumps at 45o to the horizontal. Or, he can take his chances by staying where he is in the hopes that the fire department will rescue him. You learn from the building engineers that the next building is 10 m away horizontally and the roof is 3 m below the roof of the burning building. You also know that his best long-jump distance is 7.9 m . What do you advise him to do
Answer:
y = 7.33 m, x= 3 m, t = 1.608 s
it is still higher than the second building, which indicates that if it jumps it will be saved
Explanation:
Let's use the projectile launch ratios, let's start with the range ratio
R = v₀² sin² 2θ / g
in this case the range is R = 7.9m and the angle is 45º, let's find the initial velocity
v₀² = R g / sin² 2θ
let's calculate
v₀ = [tex]\sqrt{ \frac{ 7.9 \ 9.8}{ 1} }[/tex]
v₀ = 8.80 m / s
Let's find the components of the initial velocity
v₀ₓ = v₀ cos 45 = 8.80 cos 45
[tex]v_{oy}[/tex] = v₀ sin 45 = 8.80 sin 45
v₀ₓ = 6.22 m / s
v_{oy} = 6.22 m / s
To save yourself, you have to be at the same time as the other building or higher.
x = v₀ₓ t
t = x / v₀ₓ
t = 10 / 6.22
t = 1.608 s
let's see how much it has descended in this time
y =y₀ + v_{oy} t - ½ g t²
y = 10+ 6.22 1.608 - ½ 9.8 1.608²
y = 7.33 m
therefore it is still higher than the second building, which indicates that if it jumps it will be saved
An 8.0-kg object moving with an initial velocity of 8.0 m/s on a surface comes to rest due to friction after it travels a horizontal distance of 11 m. What is the coefficient of kinetic friction between the object and the surface
Answer:
μk = 0.3
Explanation:
According the work-energy theorem, the net work done on an object, is equal to the change in the kinetic energy of the object.In this case, assuming that the object was not accelerating when moving at 8.0 m/s, the only force doing work on it, is the kinetic friction force, acting through the 11 m distance before causing the object to come to rest.The kinetic friction force, is given by the following expression:[tex]f_{frk} = \mu_{k} * F_{n} (1)[/tex]
where μk = coefficient of kinetic friction, Fn = normal force.Assuming that the surface is horizontal, since the normal force is always perpendicular to the surface, and the object is not accelerating in the vertical direction, this means that the normal force must be equal and opposite to the force that gravity exerts on the object, as follows:[tex]F_{n} = m*g (2)[/tex]
The friction force and the horizontal displacement produced by it have opposite directions, so the angle between the force and the displacement is 180º.So, we can express the work done by the kinetic friction force, as follows:[tex]W_{ffr} = -F_{fr} * d = - \mu_{k}* m*g*d (3)[/tex]
We have already said that (3) must be equal to the change in the kinetic energy, ΔK, as follows:[tex]\Delta K = K_{f} - K_{o} (4)[/tex]
Since the object comes to rest, Kf = 0.Replacing K₀ = 1/2*m*v₀² in (4), we have:[tex]\Delta K = 0 - \frac{1}{2} *m * v_{o} ^{2} = - \frac{1}{2} *m * v_{o} ^{2} (5)[/tex]
From (3) and (5), since they are equal each other, we get:[tex]W_{ffr} = \mu_{k}* g*d = \frac{1}{2} * v_{o} ^{2} (6)[/tex]
Replacing by the givens, and solving for μk, we get:[tex]\mu_{k} = \frac{1}{2} * v_{o} ^{2} *\frac{1}{g*d} =\frac{(8.0m/s)^{2}}{2*9.8m/s2*11m} = 0.3 (7)[/tex]
a plane passes over Point A with a velocity of 8,000 m/s north. Forty seconds later it passes over Point B with a velocity of 10,000 m/s north. Which is the plane's acceleration from A to B ?
Acceleration = (change in velocity) / (time for the change)
Change in velocity = (ending velocity) - (starting velocity)
Change in the plane's velocity = (10,000 m/s north) - (8,000 m/s north)
Change in the plane's velocity = 2,000 m/s north
Time for the change = 40 seconds
Acceleration = (2,000 m/s north) / (40 seconds)
Acceleration = 50 m/s² north
Earth has a mass of 5.98 1024 kg and a radius of 6.38 106 m. Assume it is a uniform solid sphere. The distance of Earth from the Sun is 1.50 1011 m. (Assume Earth completes a single rotation in 24.0 hours and orbits the Sun once every 365 Earth days.) (a) What is the rotational kinetic energy of Earth on its axis
Answer:
Explanation
Rotational kinetic energy of the earth = 1/2 Iω²
where I is moment of inertia of the earth and ω is angular velocity .
I = 2/5 m R² , m is mass and R is radius of the earth .
I = 2/5 x 5.98 x 10²⁴ x ( 6.38 x 10⁶ )²
=97.36 x 10³⁶
ω = 1 / T
T = 24 x 60 x 60 = 86400 s
ω = 1 / 86400
= 11.57 x 10⁻⁶ rad / s
Rotational Kinetic energy = 1/2 Iω²
= .5 x 97.36 x 10³⁶ x (11.57 x 10⁻⁶ )²
= 6516.54 x 10²⁴ J
A particle with charge Q and mass M has instantaneous speed uy when it is at a position where the electric potential is V. At a later time, the particle has moved a distance R away to a position where the electric potential is V2 ) Which of the following equations can be used to find the speed uz of the particle at the new position?
a. 1/2M(μ2^2-μ1^2)=Q (v1-v2)
b. 1/2M(μ2^2-μ1^2)^2=Q(v1-v2)
c. 1/2Mμ2^2=Qv1
d. 1/2Mμ2^2=1/4πx0 (Q^2/R)
Answer:
A
Explanation:
Ke = 1/2 MV^2
How is energy transferred when
hitting a nail?
Answer:
kinetic energy
kinetic energy
A power source is going to shake a string and create waves 5.0 cm in amplitude. The string has a linear mass density of 4.0x10-2 kg/m and is pulled under a tension of 100 N. The source can deliver a maximum power of 300 W. What is the highest frequency f at which the source can shake without exceeding the maximum power?
Answer:
55.13 Hz
Explanation:
Given that :
Amplitude, A =. 5cm = 0.05m
Density, d = 4 * 10^-2
Tension, T = 100N
Power = 300 W
Recall:
Power = 0.5dA²w²v
v = velocity = √T/d ; w = Angular velocity = 2πf
Rewriting our equation :
P = 0.5 * d * A² * (2πf)² * √T/d
300 = 0.5 *(4*10^-2)* 0.05² * 4π² * f² * sqrt(100/0.04)
300 = 0.5*(4*10^-2) * 0.05² * 4π² * f² * sqrt(2500)
300 = 0.02 * 50 * 0.05² * 39.478417 * f²
300 = 0.0986960 * 0.05² * f²
f² = 300 / 0.0986960
f² = 3039.6355
f = sqrt(189.97722)
f = 55.132889
= 55.13 Hz
What is the displacement of an object during a specific unit of time.
Answer:
velocity
Explanation:
the displacement of an object during a specific unit of time.
Your destroyer has a RADAR antenna height of 40 m. Using RADAR, what is the maximum detection range of a patrol boat with a mast height of 11 m above the water?
Answer:
The maximum detection range is 39.75 km
Explanation:
Given that;
Antenna height h1 = 40 m
Target height ( patrol boat mast ) h2 = 11 m
Using RADAR, what is the maximum detection range = ?
Using RADAR
we know that; Maximum detection range = (√17h1 + √17h2) km
where h1 and h2 are heights of the antenna and target height in meters
so we substitute in our values
Maximum detection range = (√(17 × 40) + √(17 × 11)) km
Maximum detection range = (√680 + √187) km
Maximum detection range = (26.0768 + 13.6747) km
Maximum detection range = (26.0768 + 13.6747) km
Maximum detection range = 39.75 km
Therefore, The maximum detection range is 39.75 km
The law of ____ states that energy in a system can change forms but can never be created or destroyed.
Answer:
The Law of Conversation
What is average acceleration due to gravity on Earth for a 2000 kg boulder, in proper SI units?
Answer:
9.8m/s²
Explanation:
The average acceleration due to gravity on Earth for a 2000kg boulder is 9.8m/s².
Every object on earth is accelerated towards the center by a rate of change of velocity with time value of 9.8m/s².
The acceleration due to gravity on earth is a constant value from places to places.
For other planetary bodies, the value varies and it differs.
But on earth every object is accelerated at 9.8m/s².
7 x 7 x 7 x.........x 7 = n (30 times)
7 is multiplied 30 times to get a number n. Which of the following will be a factor of n?
An empty parallel plate capacitor is connected between the terminals of a 5.12-V battery and charges up. The capacitor is then disconnected from the battery, and the spacing between the capacitor plates is doubled. As a result of this change, what is the new voltage between the plates of the capacitor
Answer:
V₂ = 2* V₁ = 10.24 V
Explanation:
By definition, the capacitance is given by the following relationship between the charge on one of the plates (for a parallel plate capacitor) and the voltage between them:[tex]C = \frac{Q}{V} (1)[/tex]
Applying (1) to the capacitor, once fully charged and disconnected from the battery, V = V₁ = 5.12 V.Now, we know that for a parallel plate capacitor, the capacitance is independent from the voltage applied, as follows:[tex]C = \frac{\epsilon_{0} * A}{d} (2)[/tex]
where ε₀ = 8.85*10⁻¹² F/m, A is the area of one of the plates, and d is the spacing between plates.If we double the spacing between the plates d, the capacitance will be reduced to half, due to d₂ = 2* d₁Once disconnected from the battery, due to the principle of conservation of the charge, the charge Q must remain constant, i.e.,Q₁ = Q₂ = Q
Since the only variable that can be modified is the voltage V, if the capacitance reduces to the half of the original value, the voltage must be doubled in order to keep C₂ = C₁/2, true.⇒ Q/V₂ = Q/V₁ * 1/2 ⇒ V₂ = 2* V₁ = 2* 5.12 V = 10.24 V
3. A 70 kg person climbs a 6 m ladder. How much work is required by the person?
Answer:
4116J
Explanation:
Given parameters:
Mass of the person = 70kg
Height of the ladder = 6m
Unknown:
Work done = ?
Solution:
The work done by the person climbing is the same as the potential energy.
Work done is the force applied to move a body through a distance;
So;
Potential energy = mass x acceleration due to gravity x height
Therefore;
Potential energy = 70 x 9.8 x 6 = 4116J
A woman is pushing a stroller with a baby with a mass of 8.18 kg. If the stroller is accelerating at 88.2 m/s2. How much force is she exerting?
Answer:
well you want to add 88.2 and s2.
Explanation:
The small spheres that are moving through the circuit are the electric current. Current is the flow or movement of electrons. Describe how the current moves in the simulation.
Answer:
When the circuit is connected properly, the current starts flowing from one end of the battery to the other end.
Explanation:
hope this helps!
Answer:
When the circuit is connected properly, the current starts flowing from one end of the battery to the other end.
Explanation:
Edmentum answer.
What must the charge (sign and magnitude) of a particle of mass 1.40 gg be for it to remain stationary when placed in a downward-directed electric field of magnitude 640 N/CN/C
Answer:
the charge of the particle is -2.144 x 10⁻⁵ C.
Explanation:
The force acting on the particle is calculated as;
F = EQ = mg
[tex]Q = \frac{mg}{E}[/tex]
where;
Q is magnitude of the charge of the particle
[tex]Q = \frac{(1.4\times 10^{-3})(9.8)}{640} \\\\Q = 2.144 \ \times \ 10^{-5} \ C[/tex]
since the magnetic field is acting downward, the force must be acting upward in opposite direction.
Thus, the charge of the particle will be -2.144 x 10⁻⁵ C.
A police car is traveling north on a straight road at a constant 20.0 m/sm/s. An SUV traveling north at 30.0 m/sm/s passes the police car. The driver of the SUV suspects he may be exceeding the speed limit, so just as he passes the police car he lets the SUV slow down at a constant 1.90 m/s2m/s2. How much time elapses from when the SUV passes the police car to when the police car passes the SUV
Answer:
elapsed time is 10.53 sec
Explanation:
Given that;
velocity of the car [tex]V_{P}[/tex] = 20.0m/s
Initial velocity of the SUV [tex]U_{suv}[/tex] = 30.0 m/s
SUV slow down at a constant a = 1.90 m/s²
Now, Let Vs represent the final velocity of the SUV and after time t when the police can cross it and d represent the distance both of the cars covers between the two crossing
so;
d = [tex]V_{P}[/tex] × t
also d = [tex]U_{suv}[/tex] t - 1/2 at²
so
[tex]V_{P}[/tex] × t = [tex]U_{suv}[/tex] t - 1/2 at²
we substitute
20 × t = 30 × t - 1/2 × 1.9 × t²
20t = 30t - 1/2 × 1.9 × t²
1/2 × 1.9 × t² = 30t - 20t
1/2 × 1/9 × t² = 10t
t = 2 × 10 / 1.9 ( as t ≠ 0 )
t = 20 / 1.9
t = 10.53 sec
Therefore, elapsed time is 10.53 sec
The pickup truck has a changing velocity because the pickup truck
A.can accelerate faster than the other two vehicles
B.is traveling in the opposite direction from the other two vehicles
C.is traveling on a curve in the road
D.needs a large amount of force to move
please get right i need awnser today
Answer:
C. Is traveling on a curve in the road
Hope this helps :3
The pick up truck has a changing velocity because, it is travelling on a curve in the road. A change in direction results in its change in velocity because, velocity is a vector quantity.
What is velocity ?Velocity is a physical quantity that measures the distance covered by an object per unit time. It is a vector quantity, thus having magnitude as well direction.
The rate of change in velocity is called acceleration of the object. Like velocity, acceleration also is a vector quantity. Thus, a change in magnitude or direction or change in both for velocity make the object to accelerate.
Here, all the three vehicles are travelling with the same velocity. But, the truck is moving to a curve on the road. The curvature in the path will make a change in its velocity.
Find more on velocity:
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Un autobús en una autopista lleva una magnitud de la velocidad de 95 km/h, el conductor observa que debido a un derrumbe la carretera está cerrada, en ese instante acciona los frenos, deteniendo el autobús después de recorrer 60 m. a) ¿Cuál es el valor de la aceleración en el autobús?
Answer:
La aceleración del autobús es -5.80 m/s².
Explanation:
Podemos encontrar la aceleración del autobús usando la siguiente ecuación:
[tex] v_{f}^{2} = v_{0}^{2} + 2ad [/tex]
Where:
[tex]v_{f}[/tex]: es la velocidad final = 0 (se detiene al final)
[tex]v_{0}[/tex]: es la velocidad inicial = 95 km/h
d: es la distancia recorrida = 60 m
Por lo tanto, la aceleración es:
[tex] a = \frac{v_{f}^{2} - v_{0}^{2}}{2d} = \frac{0 - (95 \frac{km}{h}*\frac{1000 m}{1 km}*\frac{1 h}{3600 s})^{2}}{2*60 m} = -5.80 m/s^{2} [/tex]
El signo negativo se debe a que el autobús está desacelerando (hasta que se detiene).
Entonces, la aceleración del autobús es -5.80 m/s².
Espero que te sea de utilidad!