Making rough estimates of physical quantities is usefulA. So that you can see if the answer to a problem makes physical sense.B. Because we only use approximate numbers in problems.C. Because the laws we use are not exact, so using exact numbers is not crucial.D.So that you can compute answers doing simpler math.

Answer:

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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

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.

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.

Answer:

A body having uniform velocity has zero acceleration because

there is not change in velocity.

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.

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.

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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Answer:

.21

Explanation:

i see everyone got it wrong so ill give you the answer, good luck :)

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

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.

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.

⇒[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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Answer:

Amur Leopard, Southeastern Russia, and northern china

Explanation:

Answer:

Amur Leopard    China/Russia

Hawks bill Turtle   live in Oceans

Here are the observations

Sugar:-

Corn syrup:-

Oil:-

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.

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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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).

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]

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.

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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Answer:

[tex]{ \bf{mechanical \: adv = \frac{load}{effort} }}[/tex]

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

Answer:

they were in the sun for long

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;

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.

Answer:

fhaiisjrbekxkrkebxnsiiwj4bnds

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]

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.

Answer:

Three

Explanation:

I hope this helps:)

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

Answer:

10 x 10⁴

I hope it's helps you

Answer:

Yes

Explanation: