Answer:
A. So that you can see if the answer to a problem makes physical sense.
Explanation:
Science can be defined as a branch of intellectual and practical study which systematically observe a body of fact in relation to the structure and behavior of non-living and living organisms (animals, plants and humans) in the natural world through experiments.
An experiment can be defined as an investigation which typically involves the process of manipulating an independent variable (the cause) in order to be able to determine or measure the dependent variable (the effect).
This ultimately implies that, an experiment can be used by scientists to show or demonstrate how a condition causes or gives rise to another i.e cause and effect, influence, behavior, etc in a sample.
Measurements refers to the process which typically involves the process of identifying and determining the dimensions of a physical object. The dimensions include important parameters such as width, height, length, area, volume, circumference etc.
In Science, making rough estimates of physical quantities is useful so that you can see if the answer to a problem makes physical sense.
For example, you could make a rough estimate of a storage tank and deductively determine whether or not it's in tandem with its physical size in reality.
Assuming Faraday constant to be 96500c/mol and relative atomic mass of copper 63,calculate the mass of copper liberated by 2A current in 5min.ans 0.196gm
Answer: The mass of copper liberated is 0.196 g.
Explanation:
The oxidation half-reaction of copper follows:
[tex]Cu\rightarrow Cu^{2+}+2e^-[/tex]
Calculating the theoretical mass deposited by using Faraday's law, which is:
[tex]m=\frac{M\times I\times t(s)}{n\times F}[/tex] ......(1)
where,
m = actual mass deposited = ? g
M = molar mass of metal = 63 g/mol
I = average current = 2 A
t = time period in seconds = 5 min = 300 s (Conversion factor: 1 min = 60 sec)
n = number of electrons exchanged = 2
F = Faraday's constant = 96500 C/mol
Putting values in equation 1, we get:
[tex]m=\frac{63 g/mol\times 2A\times 300s}{2\times 96500 C/mol}\\\\m=0.196g[/tex]
Hence, the mass of copper liberated is 0.196 g.
Tick (3) the correct statement about electrostatic charges.
(a) Earthing causes positive charges to flow from the object to the ground.
(b) Similar types of electric charges attract one another.
(c) An electroscope is used to determine the presence of electrostatic charges.
Answer:
similar type of electric charges attract one another
I think this is a coorect staement
Answer:
C ) An electroscope is used to determine the presence of electrostatic charges
In a lunar experiment, a 950-g aluminum (920 J/(°Ckg)) sphere is dropped from the space probe while is 75 m above the Lunar ground. If the sphere’s temperature increased by 0.11°C when it hits the ground, what percentage of the initial mechanical energy was absorbed as thermal energy by the aluminum sphere?
Answer:
13.759 % of the initial mechanical energy is lost as thermal energy.
Explanation:
By the First Law of Thermodynamics we know that increase in internal energy of the object ([tex]U[/tex]), in joules, is equal to the lost amount of the change in gravitational potential energy ([tex]U_{g}[/tex]), in joules:
[tex]\frac{x}{100} \cdot \Delta U_{g} = \Delta U[/tex] (1)
Where [tex]x[/tex] is the percentage of the energy loss, no unit.
By definition of the gravitational potential energy and internal energy, we expand this equation:
[tex]\frac{x\cdot m \cdot g \cdot h}{100} = m\cdot c\cdot \Delta T[/tex] (1b)
Where:
[tex]m[/tex] - Mass of the object, in kilograms.
[tex]g[/tex] - Gravitational acceleration, in meters per square second.
[tex]h[/tex] - Initial height of the object above the lunar ground, in meters.
[tex]c[/tex] - Specific heat of aluminium, in joules per degree Celsius-kilogram.
[tex]\Delta T[/tex] - Temperature increase due to collision, in degree Celsius.
If we know that [tex]m = 0.95\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]h = 75\,m[/tex], [tex]c = 920\,\frac{J}{kg\cdot ^{\circ}C}[/tex] and [tex]\Delta T = 0.11\,^{\circ}C[/tex], then the percentage of energy loss due to collision is:
[tex]x = \frac{100\cdot c\cdot \Delta T}{g\cdot h}[/tex]
[tex]x = \frac{100\cdot \left(920\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (0.11\,^{\circ}C)}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (75\,m)}[/tex]
[tex]x = 13.759\,\%[/tex]
13.759 % of the initial mechanical energy is lost as thermal energy.
A ball is dropped from the roof of a 25-m-tall building. What is the velocity of the object when it touches the ground? Suppose the ball is a perfect golf ball and it bounces such that the ve locity as it leaves the ground has the same magnitude but the op posite direction as the velocity with which it reached the ground How high will the ball bounce? Now suppose instead that the ball bounces back to a height of 20 m. What was the velocity with which it left the ground?
Answer:
a) [tex]h=25m[/tex]
b) [tex]v=19.8m/sec[/tex]
Explanation:
From the question we are told that:
Height [tex]h=25m[/tex]
Bounce Height [tex]h'=20m[/tex]
Generally the Kinematic equation is mathematically given by
[tex]V=\sqrt{2gh}\\\\V=\sqrt{2*9.81*25}[/tex]
[tex]V=22.1m/sec[/tex]
Therefore Height
[tex]h=\frac{V^2}{2g}\\\\h=\frac{22.1^2}{2*9.81}[/tex]
[tex]h=25m[/tex]
b)
Generally the Kinematic equation is mathematically given by
[tex]v^2=2ah[/tex]
[tex]v^2=2*9.8*20[/tex]
[tex]v=\sqrt{2*9.8*20}[/tex]
[tex]v=19.8m/sec[/tex]
What is the centripetal acceleration of a point on the perimeter of a bicycle wheel diameter 70.0 cm when the bike is moving 8.0 m/s? (160 m/s)
It’s 180 m/s^2 dude. I think I have you in my class lol.
The centripetal acceleration of an object is due to the changing velocity in a circular path and the centripetal acceleration of the bicycle is 182.85 m/s².
What is Centripetal acceleration?Centripetal acceleration of an object can be defined as the property of the motion of an object which is traversing a circular path. Any object which is moving in a circular path and has an acceleration vector pointed towards the center of that circular path is known as Centripetal acceleration.
The centripetal acceleration of an object can be calculated by the formula:
ac = v²/ r
where, ac = centripetal acceleration,
v = velocity of the object,
r = radius of the circular path
The centripetal acceleration of the object will be:
ac = (8)²/ r
radius = diameter/ 2
radius = 70/ 2
radius = 35cm or 0.35 m
ac = 64/ 0.35
ac = 182.85 m/s²
Therefore, the centripetal acceleration of the bicycle will be 182.85 m/s².
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(9x10^2) + (1x10^2)
10x10^4
10x10^3
1x10^4
1x10^3
Answer:
10 x 10⁴
I hope it's helps you
Answer:
Yes
Explanation:
A simple machine has efficiency 90%. What does it mean? No machine has 109 efficiency,why?
Answer:
Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.
Machines are not 100% efficient because some of the work done by a machine is used to overcome friction
.............................
State one effect of increase in heat for a temperature range of 50°C to 100°C
on Plastic
Answer:
why is fraction called a necessary evil
The heat for a temperature in plastic increases at the range of 50°C to 100°C then the plastic decreases its stiffness or flexural modulus.
It is given that the temperature is increased from 50°C to 100°C that means temperature is increasing.
It is required to state the effect of increase in heat on plastic.
What will be the effect of increase in heat for a temperature range of 50°C to 100°C on Plastic?The plastic starts to lose its stiffness or we say that it converts into a softened material as long as we increase the temperature of the material.
So if we increase the temperature too much or exceed above the limit of temperature range then it will distort.
Also there are many qualities that can be affected by increasing the temperature like mechanical property, material fatigue or chemical phenomenon.
Therefore, the heat for a temperature range of 50°C to 100°C
Plastic increases then the plastic decreases its stiffness or flexural modulus.
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A 210 Ohm resistor uses 9.28 W of power. How much current flows through the resistor? (unit=A)
Answer:
.21
Explanation:
i see everyone got it wrong so ill give you the answer, good luck :)
A man sees a deer in the road and slams on his brakes. If he is traveling at 45.2 m/s and comes to a stop in 2.74 s, what is his acceleration? O -6:02 m/s2 -0.0606 m/s2 -47.9 m/s2 0 -16.5 m/s2
Answer:
16.50 m/s²
Explanation:
initial velocity(u)=45.2 m/s
final velocity(v)= 0 (it stops)
time taken(t)= 2.74 s
now,we have
acceleration(a)= (v-u)/t
= (0-45.2 m/s)/2.74s
= -45.2 m/s / 2.74s
= -16.50 m/s²
Answer:
[tex]\boxed {\boxed {\sf -16.5 \ m/s^2}}[/tex]
Explanation:
We are asked to find the acceleration of a man driving. Acceleration is the change in velocity over the change in time. Acceleration is calculated with the following formula.
[tex]a= \frac{v_f- v_i}{t}[/tex]
The driver's initial velocity is 45.2 meters per second. His final velocity is 0 meters per second because he came to a stop. He stopped in 2.74 seconds.
[tex]\bullet \ v_f= 0 \ m/s \\\bullet \ v_i= 45.2 \ m/s \\\bullet \ t= 2.74 \ s[/tex]
Substitute these values into the formula.
[tex]a= \frac{0 \ m/s - 45.2 \ m/s }{ 2.74 \ s}[/tex]
Solve the numerator by subtracting.
[tex]a= \frac{- 45.2 \ m/s }{ 2.74 \ s}[/tex]
[tex]a= -16.49635036 \ m/s^2[/tex]
The original measurements of velocity and time have 3 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 9 in the hundredth place tells us to round the 4 in the tenths place up to a 5.
[tex]a \approx -16.5 \ m/s^2[/tex]
The acceleration is approximately -16.5 meters per second squared. The acceleration is negative because the man slowed down and came to a stop.
can someone help me asap please
Answer:
Resultant force is 20 N
Explanation:
Resolving vertically:
[tex]{ \sf{F_{y} = (8 \cos 30 \degree) + (12 \cos 30 \degree) }} \\ { \sf{ \sum F_{y} = 17.3 \: newtons }}[/tex]
Resolving horizontally:
[tex]{ \sf{F_{x} = (8 \sin 30 \degree) + (12 \sin 30 \degree) }} \\ { \sf{ \sum F _{x} = 10 \: newtons}}[/tex]
Resultant force:
[tex]{ \boxed{ \bf{F = \sqrt{ {F _{x} }^{2} + {F _{y} }^{2} } }}} \\ { \sf{F = \sqrt{ {17.3}^{2} + {10}^{2} } }} \\ { \sf{F = \sqrt{399.29} }} \\ F = 19.98 \approx20 \: newtons[/tex]
A body having uniform velocity has zero acceleration? give reason
Answer:
A body having uniform velocity has zero acceleration because
there is not change in velocity.
in a cathode-ray tube, particles are fired at the screen. What are these particles
A liquid has a density of 2 g/mL, the volume is measured at 20 mL, what is the mass of the liquid?
Answer: 40 grams, if it is two grams per mL and you have 20 mL, you multiply 2 grams/mL and you get the answer
2. ¿Puede haber trabajo en un sistema si no hay movimiento
a. Sí, si hay una fuerza siempre.
b. Sí, ya que el movimiento es sólo relativo.
c. No, ya que un sistema que no se mueve no tiene energía.
d. No, porque la ecuación de trabajo lo define.
Answer:
d. No, porque la ecuación de trabajo lo define.
Explanation:
En Física, el trabajo realizado se puede definir como la cantidad de energía transferida cuando un objeto o cuerpo se mueve a lo largo de una distancia debido a la acción de una fuerza externa.
Matemáticamente, el trabajo realizado viene dado por la fórmula;
[tex] W = F * d [/tex]
Dónde;
W es el trabajo realizado.F representa la fuerza que actúa sobre un cuerpo. d representa la distancia recorrida por el cuerpo.Por lo tanto, podemos deducir de la definición de trabajo y su fórmula que el trabajo se realiza cuando un objeto (cuerpo) se mueve una distancia o experimenta cualquier forma de desplazamiento mientras transfiere energía.
is placing a compass near a wire with live electrical current biology, chemistry, or physics?
The process of PLACING a compass wherever you want it involves Biology. Biology deals with everything that has to happen for your brain to send instructions to your muscles, your muscles to operate your arm and your hand, and your hand to move the compass to where you want it, while your eyes keep track of what's happening and send course-corrections through your brain.
Once you get the compass there and see it start doing strange things, those EFFECTS are explained by laws of nature that are covered in Physics.
Placing a compass near a wire with live electrical current involves physics. Because, the deflection in magnetic field by the current from the electrical wire is dealt with physics.
What is magnetic field ?A magnetic field is generated by the field lines originating from a magnet or an electrical coil. The moving current is always associated with a magnetic field.
A compass acts as a tiny magnet and it deflects to the north in the absence of an electrical field. If an electric field is brought in contact with the compass the needle will deflect into the direction of the magnetic field from the wire.
The strength of a magnetic field, associated electric field, magnetic flux etc. are more focused in the branches of physics. The magnetic properties of a substance is a physical property.
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3. Take sugar, oil, corn syrup, a glass and water. Pour the water in the glass and then add each of the above the substances one after the other. Observe and note your observations. And give reason for your observation.
Here are the observations
Sugar:-
Sugar is soluble in water so It will dissolve in water .Corn syrup:-
Corn syrup is also basically a sugar.It will dissolve in water too .If we shake the mixture in glass then corn syrup will be dissolved.Oil:-
Oil is not soluble in waterHence it won't dissolve in water.It will float over water and make two layerswhy Fossil fuel has been used more in the existing world ?
how to find the mechanical advantage
Answer:
[tex]{ \bf{mechanical \: adv = \frac{load}{effort} }}[/tex]
Một bóng đèn có hiệu điện thế định mức là 110V. Đặt vào hai đầu bóng đèn các hiệu điện thế sau đây, hỏi trường hợp nào dây tóc của đèn sẽ đứt?
Answer:
fhaiisjrbekxkrkebxnsiiwj4bnds
Group elements number 11 to 20 as either metallic, non metallic or metalloid.
Answer:
The elements are grouped into the different substances by color. As you can see, Lithium, Beryllium, Sodium, Magnesium, Aluminum, Potassium, and Calcium are metals out of the first 20 elements.
Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Phosphorus, Sulfur, Chlorine, and Argon, are non-metals within the first 20 elements.
Boron and Silicon count as Metalloids in the Periodic Table (properties of both metals and non-metals)
reference- socatric q and a
Explanation:
Answer:
(11-13) - Metals
(14) - Metalloid
(15-18) - Non- metals
(19-20) - Metals
Explanation:
The elements from 11 to 13 are metals. They are Sodium(Na), Magnesium(Mg) and Aluminum(Al) respectively.
The element 14 is a metalloid. It’s Silicon(Si).
The elements from 15 to 18 are non metals. The 18th element is a noble gas known as Argon(Ar).
The elements from 15 to 17 are Phosphorus(P), Sulphur(S) and Chlorine(Cl).
The elements from 19 to 20 are metals. They are Potassium(K) and Calcium(Ca).
Most solar hot water systems are fitted with gas or electric "boosters" that can also heat the water.
Describe why you think these are necessary.
DUE IN 2 HOURS PLEASE HELP!!
How does the comets energy change as it moves from point a to point d
Answer:
At point A, the comet has the least kinetic energy because the comet is resting. 3. From point B to point D its orbit's potential energy is decreasing and its kinetic energy is increasing meaning it's moving more and more
Ella is blowing up balloons in preparation for her sister's birthday. Ella finds some balloons hanging outside the house explode after a few hours. Explain why.
Answer:
they were in the sun for long
A man pulls his luggage on a 30 degree incline with a constant force of 25 N. How
much work does he do after walking 20.0 m?
a) 430 J
b) 330J
c) 1500J
d) 250 J
We know
[tex]\boxed{\sf W=Fscos\theta}[/tex]
[tex]\\ \sf\longmapsto W=25(20)cos30°[/tex]
[tex]\\ \sf\longmapsto W=500\times \dfrac{\sqrt{3}}{2}[/tex]
[tex]\\ \sf\longmapsto W=250\sqrt{3}[/tex]
[tex]\\ \sf\longmapsto W=250(1.73)[/tex]
[tex]\\ \sf\longmapsto W\approx 430J[/tex]
Option a) 430 J work done he do after walking 20.0 m.
What is work?Work, in physics, is a measure of energy transfer that happens when an object exists moved over a distance by an external force at least part of which exists involved in the direction of the displacement.
Displacement exists as the distance moved in a straight line, in a provided direction, from the starting point. Displacement exists as a vector quantity as it includes size and direction.
An angle stands the figure formed by two rays, named the sides of the angle, sharing a standard endpoint, named the vertex of the angle.
Force=F=25NDisplacement=s=20mAngle=30°⇒[tex]W=Fcos\theta[/tex]
⇒[tex]W=25(20)cos 30^{0}[/tex]
Then,
⇒[tex]W=50*\sqrt{3} /2[/tex]
⇒[tex]W=250\sqrt{3}[/tex]
Hence,
⇒[tex]W=250(1.73)[/tex]
[tex]W[/tex] approximately 430J.
Hence, Option a) 430 J work done he do after walking 20.0 m.
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if a girl is running along a straight road with uniform velocity 1.5 metre per second find the acceleration
Answer:
Acceleration is 0.
Explanation:
Since the girl is running with a uniform velocity, meaning she is moving at a constant rate, she is not accelerating. Acceleration only occurs when the speed of an object increases, decreases, or if there is a change in direction.
A car is moving with the velocity of 90km/h. If the car come to rest after 10 seconds. Calculate the final velocity and distance covered by the car within that time.
plz wirte the full formula
Answer:
you can learn from here
https://www.toppr.com/ask/en-bd/question/a-car-is-moving-with-a-velocity-of-10-ms-the-driver-sees-a-wall/
which species are near extinctions and where do they live now?
Answer:
Amur Leopard, Southeastern Russia, and northern china
Explanation:
Answer:
Amur Leopard China/Russia
Hawks bill Turtle live in Oceans
how many significant figures 216 m
Answer:
Three
Explanation:
I hope this helps:)
