An 80 kg skateboarder moving at 3 m/s pushes off with her back foot to move faster. If her velocity increases to 5 m/s, what is her change in kinetic energy as a result? J How much work did she perform? J

The question is incomplete as it does not have the options which are:

The waves have a trough.

Particles move only small distances.

particles travel the length of the wave, moving in an up-and-down motion.

The waves have a crest.

The energy is transferred perpendicular to the direction of the wave motion.

Answer:

Explanation:

Transverse waves are the waves which can be characterised easily by their oscillation in a perpendicular direction to the path of the wave propagation.

The particle follows the wave nature and moves only to a small distance like ripples in the water and these waves possess the trough, the lower part and the crest the upper part.

These waves can be observed in ripples of the water, in a string of the guitar while playing and the electromagnetic waves.

Thus, the selected options are correct.

Answer:

Total Cost is 41.18 AED

Explanation:

Per day number of hours light bulbs were on=3hours

5 bulbs power consumption = 150Wx5 = 750W

Electricity usage per day = 750 x 3 = 2250Wh = 2.25kWh

April has 30 days and May has 31 days. Therefore totals days = 61days

Total power consumption = 2.25x 61 = 137.25kWh

Total Cost = 137.25x 0.30 = 41.175 AED

Answer  34

Explanation:

Answer:

The dog moved 6 meters west and 34 meters total

Explanation:

Answer:

1.) Chemical Change - a change in matter that results in a change in its identity and properties

2.) Combustibility - the ability of a substance to burn

3.) Reactivity - The ability of a substance to combine Chemically with another

4.) Chemical Property - the ability of matter to change into a different substance

Explanation:

Proof: -Image Below & the definitions for each word-

Chemical Change- Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. ... An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen.

Combustibility- Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion. This is an important property to consider when a substance is used for construction or is being stored. It is also important in processes that produce combustible substances as a by-product.

Reactivity- In chemistry, reactivity is the impetus for which a chemical substance undergoes a chemical reaction, either by itself or with other materials, with an overall release of energy.

Chemical Property- A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity. ... They can also be useful to identify an unknown substance or to separate or purify it from other substances.

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Chemical change - A change in a substance that brings a change in its identity and properties

Combustibility - The ability of a substance to bursts into the combustion

Reactivity - The ability of a matter to chemically combine with others.

Chemical Property - The ability of a substance to change into a completely different substance.

Chemical changes take place when a substance combines with another substance to create a new substance, called chemical synthesis. An example of a chemical change is the formation of sodium hydroxide and hydrogen by the reaction between sodium and water.

Combustibility determines how easily a substance can burst into flame, through combustion. The combustibility is a property to consider when a substance is used for storage or for construction. It is also an important property in processes where the formation of combustible substances is a side product.

In chemistry, reactivity is the property of a chemical substance that undergoes a chemical reaction with itself or with other chemicals,  and the overall release of energy.

Chemical properties are the characteristics of a particular substance that can be noticed during a chemical reaction. Some major chemical properties include heat of combustion, flammability, rate of radioactive decay, toxicity, pH value, and chemical stability.

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Answer:

can you make it clear i do not understand.

Explanation:

Answer:

Explanation:

Assuming the machine is a simple machine, such as a lever or pulley, the machine will not do any more work than is put into it. However, it can change the magnitude or direction (or both) of the input force required to achieve a particular output force.

Because the machine does not increase the work done, if the output force is greater, the output distance must be less.

The applicable observations are ...

Answer:

process of recombination

Explanation:

this process happens when 2 molecules of DNA exchange pieces of their genetic material with each other

Answer:

light bends away from the normal when it moves from air into water-refraction

Answer: C.) Light slows down when it moves from air into water.

Explanation: i hope this helps :)

Answer:

The relationship between light and matter produces three phenomena, namely:

Explanation:

In everyday use, reflective materials are used on construction apparel, handheld electric torch, headlamp of vehicles etc.

     2. Absorption:  When matter captures electromagnetic radiation, it converts the energy of photons into internal energy and absorption is said to have taken place.  

Light absorption by the chlorophyll in plants for use in production is an example of how humans use light absorption albeit indirectly.

     3.  Transmission        

When matter is transparent or semi-transparent it allows light to pass through. For semi-transparent matter, some of the light is absorbed.

Transmission of light is used predominantly in various kinds of lighting effects for interior decoration and houses.

     4. Emission

When matter releases energy as light, it is said to have emitted light.

Examples of everyday emission of light include Light Emitting Diode which is used in remote controls.

Cheers!

Answer:

The reading of the Geiger counter, 22 minutes later = 29 counts per minute (cpm)

Explanation:

Half life is defined as the time taken for the amount ( or activity) of a substance to reduce to half its original value.

As stated in the question, the half life of Francium-233 is 22 minutes, [tex]t_{1/2} = 22 minutes[/tex]. This means that it takes 22 minutes for the activity of Francium-233 to reduce to half of its original value.

The original activity of Francium-233 =  58 counts per minute (cpm)

By the end of 22 minutes, the activity measured by the counter would have halved.

Activity of Francium-233 after 22 minutes = 58/2

Activity of Francium-233 after 22 minutes = 29 counts per minute (cpm)

Answer:

1. For acidifying stomach content. Hydrochloric acid is the main component

2. Prevents Infections. Hydrochloric acid acts as a barrier against foreign microorganisms

3. Helps in digestion of food. The hydrochloric acid present in the gastric acid.

So basically it helps digest food in the stomach.

Hey!!!

Mechanical energy is the sum of kinetic energy and potential energy.

Hope it helps..

Good luck on your assignment

Answer:

1°C

Explanation:

Water freezes at 0°C, 32°F, and 273°K.

The only temperature warmer than the freezing point is 1°C.

Answer:

A. 0 F

Explanation:

Test approved

Answer:

The period of a pendulum does not depend on the mass of the ball, but only on the length of the string.

Explanation:

Two pendula with different masses but the same length will have the same period. Two pendula with different lengths will different periods; the pendulum with the longer string will have the longer period.

Answer:

0.024m^3

Explanation:

=======

Answer:

=======

Given:-

Mass of the block of wood = 24 kg

Volume of wood = 0.032 m^3

Density of water = 1000kg/m^3

Now,

Density of wood is given by,

\frac{m}{v} = \frac{24}{0.032} \\

\frac{m}{v} = 750 \: kg/m ^{3}

Therefore,

The density of wood is 750kg/m^3

By principle of floatation,

Mass \:of\: wood = Mass\: of\: liquid \:displaced

Therefore,

Mass of liquid displaced = 24kg

Volume of liquid displaced (v),

\frac{m}{v} = \frac{24}{1000} \\

\frac{m}{v} = 0.24m ^{3}

Now,

Since the volume of the wood is equal to the volume of water displaced, it is 0.024m^3

=====

Note:

=====

=> The volume of the wood below the water surface is the volume of water displaced.

=> Buoyant\: force = Weight\: of\: the \:displaced\: water.

Answer:

Length of longer pendulum = 99.3 cm

Length of shorter pendulum = 82.2 cm

Explanation:

Since the longer pendulum undergoes 10 oscillations in 20 s, its period T = 20 s/10 = 2 s.

From T = 2π√(l/g), the length of the pendulum. l = T²g/4π²

substituting T = 2s and g = 9.8 m/s² we have

l = T²g/4π²

= (2 s)² × 9.8 m/s² ÷ 4π²

= 39.2 m ÷ 4π²

= 0.993 m

= 99.3 cm

Now, for the shorter pendulum to be in step with the longer pendulum, it must have completed some oscillations more than the longer pendulum. Let x be the number of oscillations more in t = 20 s. Let n₁ = number of oscillations of longer pendulum and n₂ = number of oscillations of longer pendulum.

So, n₂ = n₁ + x. Also n₁ = t/T₁ and n₂ = t/T₂ where T₂ = period of shorter pendulum.

t/T₂ = t/T₁ + x

1/T₂ = 1/T₁ + x  (1)

Also, the T₂ = t/n₂ = t/(n₁ + x)  (2)

From (1) T₂ = T₁/(T₁ + x) (3)

equating (2) and (3) we have

t/(n₁ + x) = T₁/(T₁ + x)

substituting t = 20 s and n₁ = 10 and T₁ = 2s, we have

20 s/(10 + x) = 2/(2 + x)

10/(10 + x) = 1/(2 + x)

(10 + x)/10 = (2 + x)

(10 + x) = 10(2 + x)

10 + x = 20 + 10x

collecting like terms

10x - x = 20 - 10

9x = 10

x = 10/9

x = 1.11

x ≅ 1 oscillation

substituting x into (2)

T₂ = t/n₂ = t/(n₁ + x)

= 20/(10 + 1)

= 20/11

= 1.82 s

Since length l = T²g/4π²

substituting T = 1.82 s and g = 9.8 m/s² we have

l = T²g/4π²

= (1.82 s)² × 9.8 m/s² ÷ 4π²

= 32.46 m ÷ 4π²

= 0.822 m

= 82.2 cm

Answer:

B:  Only the ball experiences no resistive force to its state of motion.

Answer:

A) Independent

B) Dependent

C) Mass

Explanation:

The speed applied to the physics cart is manipulated. This doesn't depend on another variable. Thus, speed is the (independent) variable.

The cart accelerates due to the speed applied to the cart. Acceleration depends on the speed applied. Thus, acceleration is therefore the (dependent) variable.

A “constant” is a parameter that remains the same regardless of the variables.

One parameter of the cart that is held constant is the (mass).

Answer:

The tin fork and knife, the copper coin, and the steel fence pole.

Explanation:

Those are both what people would call soft metals so they are malleable to the extent of probably not needing heavy duty equipment. It depends on you description of malleable because the steel fence pole could be malleable with the correct equipment and not snap in half if bent slowly enough.

The definition of malleable: (of a metal or other material) able to be hammered or pressed permanently out of shape without breaking or cracking.

But the glass table, marble sculpture and antique ceramic vase are nowhere near malleable because if you tried bending them they wouldn't bend but would shatter and break into pieces.

The tin fork and knife, the copper coin, and the steel fence pole are malleable, the correct option is A, C, and F.

A malleable material is one that can be easily formed into a thin sheet by hammering. The most malleable metal is gold. In contrast, ductility is a solid material's ability to deform under tensile stress.

Metals are malleable because when a force is applied, layers of ions can slide over each other. Metallic bonding allows metal to change shape without breaking.

Gold, iron, aluminum, copper, silver, and lead are examples of malleable metals. Ductility and malleability do not always correlate; for example, gold is both ductile and malleable, whereas lead is only malleable.

Tin fork and knife, copper coin, and steel fence pole are all malleable.

Thus, the correct options are A, C, and F.

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Answer:

a and c

Explanation:

a)light moves in a straight line and distracts when it encounters an obstacle forming a shadow

c)the light rays from that object or also tgose from the image must enter your eye for you to see that image

Answer:

x = 1.43 cm

Explanation:

The horizontal displacement of the pendulum can be found using the following equation:

[tex] x(t) = x_{0}*sin(\omega*t + \phi) [/tex]

Where:

x₀: is the initial horizontal displacement = 10 cm

ω: is the angular frequency

t: is the time = 5 s

Φ: is the phase shift = 20° = 20*2π/360 = 0.35 rad        

The angular frequency can be calculated using the oscillation perid (T):

[tex] \omega = \frac{2\pi}{T} = \frac{2\pi}{4 s} = 1.57 rad/s [/tex]  

The horizontal displacement is:

[tex] x(t) = x_{0}*sin(\omega*t + \phi) = 10 cm*sin(1.57 rad/s*5 s + 0.35 rad) = 1.43 cm [/tex]    

Therefore, the displacement of the pendulum at 5 s is 1.43 cm.

I hope it helps you!

Answer:

Electrons

Atomic number

Explanation:

The question describes a period table which is a chart of the elements.

The Periodic Table of elements shows the arrangement of elements based on their increasing atomic number.

In a neutral atom, the number of electrons will equal the number of protons, so we can easily determine electron number from atomic number. In addition, the position of an element in the periodic table—its column, or group, and row, or period—provides useful information about how those electrons are arranged (electronic configuration) in their different shells.

It is a way to display to number of ____electrons____ for elements. This chart will show the correlation between __atomic____ number and the number of valence electrons

Answer:

Revolutions made before attaining angular velocity of 30 rad/s:

θ = 3.92 revolutions

Explanation:

Given that:

L(final) = 10.7 kgm²/s

L(initial) = 0

time = 8s

Torque is the rate of change of angular momentum:

[tex]T = \frac{L(final)-L(initial)}{t}\\T = \frac{10.7-0}{8}\\T=1.34 Nm[/tex]

We know that

T = Iα

α = T/I

where I = moment of inertia = 2.2kgm²

α = 1.34/2.2

α = 0.61 rad/s²

We know that angular equation of motion is:

ω²(final) = ω²(initial) +2αθ

(30 rad/s)² = 0 + 2(0.61 rad/s²)θ

θ = (30 rad/s)²/ 2(0.61 rad/s²)

θ = 24.6 radians

Convert it into revolutions:

θ = 24.6/ 2π

θ = 3.92 revolutions

Answer: 48

Explanation:

Given the expression (5x + 4y)/2

Where x represents the valence of Argon and y represents the summation or valencies of sulphur and Neon

A neutral Argon, Sulphur and Neon will have :

The valence of Argon = 8

The valence of sulphur = 6

The valence of Neon = 8

Therefore, X = 8 and Y = 6 + 8 = 14

Substitute x and y into the expression.

(5x + 4y)/2 = (5×8 + 4×14)/2

(40 + 56)/2 = 96/2 = 48

Evaluating: (5x + 4y)/2 = 48

Answer:

f = 215.27 Hz

Explanation:

We have,

An open-pipe resonator has a length of 2.39 m.

It is required to find the frequency of its third harmonic if the speed of sound is 343 m/s.

For third harmonic, its length is equal to, [tex]l=\dfrac{3\lambda}{2}[/tex]

So,

[tex]\dfrac{3v}{2f}=2.39[/tex]

f is frequency in its third harmonics

[tex]f=\dfrac{3v}{2\times 2.39}\\\\f=\dfrac{3\times 343}{2\times 2.39}\\\\f=215.27\ Hz[/tex]

So, the frequency of its third harmonic is 215.27 Hz.

false

hope this help

lf I'm write can you give me a brainlist please

Given that,

Voltage = 10 volt

Suppose, The three resistance is connected in parallel and each resistance is 12 Ω. find the current in the electric circuit.

We need to calculate the equivalent resistance

Using formula of parallel

[tex]\dfrac{1}{R}=\dfrac{1}{R_{1}}+\dfrac{1}{R_{2}}+\dfrac{1}{R_{3}}[/tex]

Put the value into the formula

[tex]\dfrac{1}{R}=\dfrac{1}{12}+\dfrac{1}{12}+\dfrac{1}{12}[/tex]

[tex]\dfrac{1}{R}=\dfrac{1}{4}[/tex]

[tex]R=4\ \Omega[/tex]

We need to calculate the current in the circuit

Using ohm's law

[tex]V=IR[/tex]

[tex]I=\dfrac{V}{R}[/tex]

Where, V = voltage

R = resistance

Put the value into the formula

[tex]I=\dfrac{10}{4}[/tex]

[tex]I=2.5\ A[/tex]

Hence, The current in the circuit is 2.5 A

Answer:

0.08 J

Explanation:

EE = ½ kx²

EE = ½ (400 N/m) (0.02 m)²

EE = 0.08 J

The energy stored in the spring, if the force constant is 400N/m is 0.08 J.

When the spring is compressed, it gets compressed up to its elastic limit. When load is removed from the spring, it regains its shape and obtains equilibrium position. The energy stored in this process is called  as spring potential energy.

Given a spring is compressed by 0.02m. The force constant is 400N/m. The energy stored in the spring is given by

SPE = ½ kx²

SPE = ½ (400 N/m) (0.02 m)²

SPE = 0.08 J

Thus, the energy stored in the spring is 0.08 J.

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Answer:

Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.

Answer:

Explanation shown below.

Explanation:

Is one generated from the movement of free moving electrons.

Electric energy can be harnessed from different sources.