IMPORTANT 3 QUESTIONS!

Answer:

(B) Parachutes

Explanation:

Air resistance works to slow down trains and airplanes, so it isn't desirable.  Air resistance also causes pendulums to slow and stop.

Parachutes need air resistance to slow a person's fall.  So air resistance is desirable here.

Answer:

B i answered it it it

Explanation:

Explanation:

Hello there!!!

You just need to use simple formula for force and momentum,

F= m.a

and momentum (p)= m.v

where m= mass

v= velocity.

a= acceleration .

And the solutions are in pictures.

Hope it helps..

Answer:

a) 0.73A

b) 0.23A

c) 2.76V

Explanation:

We need to first resolve the two resistors in series. The resistors in series are

12 Ω and 3 Ω  AND 6 Ω and 3 Ω

For  12 Ω and 3 Ω in series, total effective resistance =  12 Ω + 3 Ω = 15 Ω

For  6 Ω and 3 Ω in series, total effective resistance =  6 Ω + 3 Ω = 9 Ω

Since the equivalent series resistors i.e 15Ω ND 9Ω are connected in parallel, the total effective resistance Rt will be expressed as;

1/Rt = 1/15+1/9

1/Rt = (3+5)/45

1/Rt = 8/45

Rt = 45/8 Ω

a) If a potential difference of 4 V is applied across it, the total current I in the circuit can be derives using the ohms law.

According to the law E = IRt

Given E = 4V, Rt = 45/8

I = E/Rt

I = 4/(45/8)

I = 4 * 8/45

I = 32/45

I = 0.73A

Hence, the current drawn from the battery is 0.73A

b) Before we can calculate the current in the 12Ω resistor, we need to calculate the current in the equivalent resistance of 15Ω(sum of 12Ω and 3Ω)

Current in the 15Ω resistor = Voltage across the 15Ω resistor/Resistance

Current in the 15Ω resistor = 4/15

Current in the 15Ω resistor = 0.27A

Since the same current flows in a series connected resistors, hence the correct in the 12ohms resistor is also 0.27A.

c) Before we can calculate the pd across the 6ohms resistor, we need to know the voltage across the effective resistance of 9ohms(6ohms+3ohms). The pd across the 9ohm resistance will be the same as the source voltage i.e 4Volts.

We will need to share this 4volts between the 6ohms and the 3ohms using ohms law.

According to the law, V = IR

For the 6ohms resistor, voltage across it will be;

V = (0.73-0.27)×6

V= 0.46×6

V = 2.76Volts.

Hence the voltage across the 6ohms resistor is 2.76V.

Answer:

266. 4

Explanation:

acceleration due to vravity on earth is 10m/s.

One third of it is (1/3)*10

=3.333m/s.

Weight is mass × acceleration

weight= 80kg÷ 3.333m/s

W= 266.4 Newton.

Answer:

Explanation:

We shall represent the point of destination and point of new starting point in vector form .

i and j will represent east and north .

point of destination = 123 j

starting point = 112 i

distance between the two

D = 123 j - 112 i

magnitude of D = √ ( 123² + 112² )

= 166.35 km

Direction of D

Tanθ = -  123 / 112

= - 1.09

θ = 132.54 degree from east in positive angle .

Answer:

If max height = 1.1 meters, then initial velocity is 3.28 m/s

If max height is 1.1 feet, then the initial velocity is 5.93  ft/s

Explanation:

Recall the formulas for vertical motion under the acceleration of gravity;

for the vertical velocity of the object we have

[tex]v=v_0-g \,t[/tex]

for the object's vertical displacement we have

[tex]y-y_0=v_0\,t - \frac{g}{2} \,t^2[/tex]

If the maximum height reached by the object is given in meters, we use the value for g in [tex]m/s^2[/tex] which is: [tex]9.8\,\,m/s^2[/tex]

If the maximum height of the object is given in feet, we use the value for g in  [tex]ft/s^2[/tex]  which is : [tex]32\,\,ft/s^2[/tex]

Now, when the ball reaches its maximum height, the ball's velocity is zero, so that allows us to solve for the time (t) the process of reaching the max height takes:

[tex]v=v_0-g \,t\\0=v_0-g \,t\\g\,\,t=v_0\\t=\frac{v_0}{g}[/tex]

and now we use this to express the maximum height in the second equation we typed:

[tex]y-y_0=v_0\,t - \frac{g}{2} \,t^2\\max\,height=v_0\,(\frac{v_0}{g}) - \frac{g}{2} \,(\frac{v_0}{g})^2\\max\,height= \frac{v_0^2}{2\,g}[/tex]

Then if the max height is 1.1 meters, we use the following formula to solve for [tex]v_0[/tex]:

[tex]1.1= \frac{v_0^2}{2\,9.8}\\(9.8)\,(1.1)=v_0^2\\v_0=10.78\\v_0=\sqrt{10.78} \\v_0=3.28\,\,m/s[/tex]

If the max height is 1.1 feet, we use the following formula to solve for [tex]v_0[/tex]:

[tex]1.1= \frac{v_0^2}{2\,32}\\(32)\,(1.1)=v_0^2\\v_0=35.2\\v_0=\sqrt{35.2} \\v_0=5.93\,\,ft/s[/tex]

Answer:

11

Explanation:

for khan academy, this is the answer

Answer:

Sound travels fastest through solids.

Explanation:

This is because molecules in a solid medium are much closer together than those in a liquid or gas, allowing sound waves to travel more quickly through it. In fact, sound waves travel over 17 times faster through steel than through air.

Sound waves move the fastest through the solid. The speed of the sound wave  in the liquid and gas is low,

A sound wave is produced when a medium begins to vibrate. When an entity vibrates, a pressure wave is formed, which causes sound.

Solids transmit sound the fastest. Because the molecules in a solid medium are much closer together than in a liquid or gas, sound waves can move through it much faster.

Hence, sound waves move the fastest through the solid.

To learn more about the sound wave, refer to the link;

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Answer:

A person climbs a set of stairs

Explanation:

Potential energy is said to be possessed by an object due to its position. As the height from the ground level increase, the potential energy increases. It is calculated by the below formula as :

P = mgh

Out of the given options, the option that illustrates an increase in potential energy is option (b) i.e. a person climbs a set of stairs. As he steps one stair, its position from ground increases. It means its potential energy increases.

Answer:

Magnitude of Force : 0.8 N

Explanation:

We know that the velocity of this particle changes from 15ms⁻¹, or in other words 15m / s, to the respective velocity 25m / s over the course of 2.5 seconds. Given this information we can determine the acceleration of the particle,

a = v₁ - v₂ / t = 25 - 15 / 2.5 = 10 / 2.5 = 4m / s²

Knowing the acceleration we can calculate the magnitude of the force using the formula f = ma - Newton's second law of motion,

f = m [tex]*[/tex] a = 200g [tex]*[/tex] 4m / s² = 800 g [tex]*[/tex] m / s²

Remember however that Newtons are in the standard units kg [tex]*[/tex] m / s². Therefore we have to convert 800 g to kg to receive our solution,

800 g = 800 / 1000 kg = 0.8 kg,

Magnitude of Force = 0.8 N ; Solution = Option B

Answer:

С. a single component that can't be separated

Explanation:

Substance : It is the pure form of matter or we can say that it is a matter that contains only one type of molecule of atom. It can not be separated by physical process.

For example : Water is a substance.

Mixture : It is a combination of different type of atoms or molecules and it is an impure form.

For example : Sodium chloride with water is a mixture.

Hence, the correct option is, (C) a single component that can’t be separated.

A substance is a single component that can't be separated by the physical process therefore the correct answer is option C.

A chemical compound is a mixture of two or more chemical components, whether they are related or unrelated.

For instance, the molecular H2O is composed of one hydrogen atom and two oxygen atoms.

For instance, water is a material that cannot be physically divided yet may be separated using electrolysis.

Mixture: This impure form is made up of several different kinds of atoms or molecules.

A mixture is, for instance, sodium chloride and water.

As a result, (C), a single, irreducible component, is the right answer.

To learn more about a chemical compound here, refer to the link;

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Answer:

The area of the sheet of metal = 4.255 m²

The volume of the sheet of metal = 0.08553 m³

Explanation:

The area of a rectangle is given by the following relation;

Area, A = Length × Breadth

Therefore, the area of the rectangular sheet of metal, A[tex]_m[/tex], is given as follows;

A[tex]_m[/tex]  = 4.234 m × 1.005 m = 4.255 m²

The area of the sheet of metal = 4.255 m²

The volume of the metal sheet id given by the relation, volume V[tex]_m[/tex]= area × Thickness

The thickness of the sheet of metal = 2.01 cm = 0.0201 m

Therefore,

V[tex]_m[/tex] = 4.255 m × 0.0201 m = 0.08553 m³

The volume of the sheet of metal = 0.08553 m³.

Answer:

Are yarr mei bhi Indian hu.....

Explanation:

Tumse milkar accha laga

Answer:

d = 343 m

Explanation:

Given that,

You notice that an echo took 2 seconds before you heard the echo of your yell.

We need to find that how far away is the canyon wall that reflected your yell. It means we need to find the distance.

The distance covered by an object is given by :

d = v × t

v is speed of sound in air, v = 343 m/s

The sound took 1 s to reach the wall and 1 s back to you.

It means that,

d = 343 × 1

d = 343 m

So, canyon will reflect your yell at a distance of 343 m

Explanation:

Earth’s orbit around the Sun represented as :

1 AU = 4 inches

Therefore,

Inner edge of the Oort Cloud represented as :

10,000 AU = 40,000 / 63360 = 0.631 miles

Outer edge of the Oort Cloud represented as:

100,000 AU = 400,000 / 63360 = 6.31 miles

Answer:

1) Tailored software  Library management system

2) Utility software Scan viruses

3) Operating system Used to coordinate the hardware of the computer

4) Packaged software set of programs Microsoft office

Explanation:

1) A tailored software, also known as a custom software, is one that is designed and tailor-made only for a particular organisation

2) A utility software is a computer maintenance and analysis software used to enable proper functioning of the computer by performing restorative and maintenance tasks

3) Operating system software

The operating system software controls the operation of the computer hardware within the system and enables the operation of other programs in the computer

4) Packaged software are a collection of programs that are oriented to perform interrelated tasks that a focused to a particular area, such as Microsoft Office.

Answer:

comparative----more famous, superlative----- most famous

[tex]\huge{\fbox{\red{Answer:}}}[/tex]

Famous

___________________✍

Comparative Form : more famous

Superlative Form : most famous

Hope you understand❣

Answer:

[tex]\phi=1.56\times 10^{-5}\ Wb[/tex]

Explanation:

Given that,

Emf, V = 22 mV

Number of turns in the coil us 519

Rate of change of current is 10 A/s.

We need to find the magnetic flux through each turn of the coil at an instant when the current is 3.70 A.

Let's find the inductance first. So,

[tex]L=\dfrac{\epsilon}{(dI/dt)}\\\\L=\dfrac{0.022}{10}\\\\L=0.0022\ H[/tex]

We have,

[tex]L=\dfrac{N\phi}{I}[/tex], [tex]\phi[/tex] is magnetic flux

[tex]\phi=\dfrac{LI}{N}\\\\\phi=\dfrac{0.0022\times3.7}{519}\\\\\phi=1.56\times 10^{-5}\ Wb[/tex]

So, the magnetic flux is [tex]1.56\times 10^{-5}\ Wb[/tex].

Answer:

1. option a

2. option d

Explanation:

HOPE IT HELPS YOU

Answer:

[tex]1.5 * 10^6[/tex]

Explanation:

Given

Digit: 1,500,000

Required

Represent using scientific notation

We start by expressing the given digit as a product of 1.5 and a multiple of 10

[tex]Digit = 1.5 * 1,000,000[/tex]

1,000,000 can be represented as 10⁶

So; the digit becomes

[tex]Digit = 1.5 * 10^6[/tex]

Hence, the scientific notation of 1,500,000 is 1.5 * 10⁶

Answer:

the partial pressure of nitrogen after the air has been heated is 2.61atm

Explanation:

Using combined gas law which is the combination of Boyle's Law and Charles' Law, and it gives The relationship between pressure, volume, and absolute temperature

PV/T= K

P1₁V₁/T₁=P₂V2₂/T₂

P₂=final pressure= ?

P₁= initial pressure=2.45 atm

.T₁= initial temperature= 273k

T₂= final temperature= 550 K,

We can make P₂ subject of the formula then we have

P₂=P₁V₁T₂/T₁T₂

=( 2.45×8×550)/(273×11.8)

P2=3.35atm

Now we can calculate the partial pressure of N₂

N₂= 3.35×(78.08/10)

=2.61atm

Therefore, the partial pressure of nitrogen after the air has been heated is 2.61atm

Answer:

True

Explanation:

This is in fact what the Archimedes principle states, and what he used in the famous anecdote about finding if  the crown of the King was really made of gold.

Answer:

1st question c part

2nd question c part

Answer:

The limits of our senses are

Limits of Sight

Our vision field of view is 120° sideways and 135° vertically

Angular visual resolution is about an 1/60 of one degree

The presence of blind spots in the eyes

Limits of sound

The hearing range is within 20 - 20,000 Hz and our threshold hearing above 0 to 5 decibel of sound

Limits of taste

We have very limited sense of taste which is partly dependent on our sense of smell with little objectivity in distinguishing tastes

Sense of smell

The establishing of the effectiveness of human sense of smell is gauged on numerous parameters with certain tests being inconsistent, as such, it is difficult to clearly establish the effectiveness of the human sense of smell

In comparison with the sense of smell of other living things such as dogs, the human sense organ is comparatively low

Explanation:

Answer:

3.33 N

Explanation:

First, find the acceleration.

Given:

Δx = 3 m

v₀ = 0 m/s

t = 3 s

Find: a

Δx = v₀ t + ½ at²

3 m = (0 m/s) (3 s) + ½ a (3 s)²

a = ⅔ m/s²

Use Newton's second law to find the force.

F = ma

F = (5 kg) (⅔ m/s²)

F ≈ 3.33 N

Answer:

Balanced forces

Explanation:

Answer:

its balance force

Explanation:

Answer:

22.73 m/s or 81.72 kph

Explanation

We can find the combined mass of both cars as

970 kg + 2300 kg = 3270 kg.

Then the normal force of the cars can be calculated as

F(n)= mg

Where g is acceleration due to gravity 9.8m/s^2

3270 kg ×9.8 = 32046 kg*m/s^2.

coefficient of kinetic friction between tires and road to be 0.80 × F(n)

Then the frictional force can be calculated as

= (32046kg*m/s^2 × 0.80 )

= 25636.8 kg*m/s^2

We can now calculate the work done that was used stopping the cars as

Frictional force × distance

(25636.8 kg*m/s^2 ) × 2.9m= 74346.72kg*m^2/s^2

From kinetic energy formula, the combined velocity of the car can be determined

E=0.5 M V²

√(2E/M) = V

√(2*74346.72kg*m^2/s^2 / 3270 kg) = V

V= √ (45.472)

V=6.743293m/s

the momentum of both cars can be determined as

6.743293m/s * 3270 kg

= 22050.57kg*m/s

Now the final momentum of both cars must be equal to the the momentum of

the sports car just prior to the collision. Therefore, the speed of the sports car at impact.

=(22050.57 kg*m/s) / 970 kg = 22.73 m/s

We can convert that to km/h.

22.73 m/s * 3600 s/h / 1000 m/km = 81.72 kph

Answer:

From the graph, at t = 5 seconds, the velocity = 50 m/s as shown also in the above table

Please find attached the graph

Explanation:

The initial velocity of the body =  m/s

The acceleration of the body = 8 m/s²

The velocity after 5 seconds can be determined graphically and by calculation as follows;

Graphically, we have the data points which can be found by the straight line relation  v = u + a×t,

Where ,

a = The slope = 8 m/s²

u = 10 m/s = The y-intercept

Which gives;

v = 10 + 8 × t

The following data can be calculated for various time t;

Time, t     Velocity , v

0,             10

1,              18

2,             26

3,             34

4,             42

5,             50

6,             58

From the graph, at t = 5 seconds, the velocity = 50 m/s as shown also in the above table

Please find attached the graph

By calculation, we have;

v = u + a×t

Where;

v = The final velocity

u = The initial velocity = 10 m/s

a = The acceleration = 8 m/s²

t = The time = 5 seconds

v = 10 + 5× 8 = 50 m/s.

Answer:

V = 26.6 volts

Explanation:

Let Initial Potential Difference be V.

Charge (Q) accumulated in 30 mF Capacitor =

Q = C * V

Q= 30 * V

Now, Common Potential after connecting to uncharged 10mF capacitor in parallel = 20 Volt

Total Charge =Total Capacity * Common Potential

30 * V = ( 30 + 10) * 20

V = 26.6 volts

The unknown potential across the 30-µF capacitor is 6.67 V.

The given parameters;

Since the potential difference between the two capacitors are different, the two capacitors are in series connection.

In series circuit arrangement, the quantity of charge flowing in each capacitor is the same.

[tex]Q_{30\ \mu F} = Q_{10 \ \mu F}[/tex]

[tex]Q_{10 \ \mu F} = CV = 10\times 10^{-6} \times 20 = 0.0002 \ C[/tex]

The potential difference are different and the total potential is given as;

[tex]V_{T} = V_1 + V_2\\\\V_1 = \frac{Q}{C_1} \\\\V_2 = \frac{Q}{C_2} \\\\V_1+V_2 = \frac{Q}{C_1} + \frac{Q}{C_2}\\\\V_1 + V_2 = Q(\frac{1}{C_1} + \frac{1}{C_2} )\\\\V_1 + 20 = Q(\frac{1}{C_1} + \frac{1}{C_2} )\\\\V_1+ 20 = \frac{Q(C_2+ C_1)}{C_1 C_2} \\\\V_1 = \frac{Q(C_2+ C_1)}{C_1 C_2} - 20[/tex]

[tex]V_1 = \frac{0.0002(10\times 10^{-6}\ + \ 30\times 10^{-6})}{(30\times 10^{-6}) (10\times 10^{-6})} - 20\\\\V_1 = \frac{8\times 10^{-9}}{3\times 10^{-10}} - 20\\\\V_1 = 26.67 - 20\\\\V_1 = 6.67 \ V[/tex]

Thus, the unknown potential across the 30-µF capacitor is 6.67 V.

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Answer:

The answers to your questions are given below

Explanation:

A. Definition of momentum.

Momentum of an object can be defined as the product of the mass of the object and its velocity. Mathematically, it expreessed as:

Momentum = mass x Velocity

From the above equation, we can derive the SI unit of momentum as follow:

Mass is measured in Kilogram (Kg)

Velocity is measured in meter per second (ms¯¹).

Momentum = mass x Velocity

Momentum = Kg x ms¯¹

Momentum = Kg•ms¯¹

Therefore, the SI unit of momentum is Kg•ms¯¹.

Bi. Determination of the force of the body from O to A.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Acceleration (a) =.?

a = v/t

a = 40/2

a = 20 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 20 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 20

F = 100 N

Therefore, the force of the body from O to A is 100 N.

Bii. Determination of the force of the body from B to C.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 10 – 6 = 4 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 4 secs.

Acceleration (a) =.?

a = v/t

a = 40/4

a = 10 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 10 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 10

F = 50 N

Therefore, the force of the body from B to C is 50 N.

Answer:

Thomson’s model

Explanation:

Thompson regarded the atom largely as a sphere of positively charged matter in which negative charges were embedded.

This came to be known as the plum pudding model of the atom because it resembles a pudding studded with currants.

This was an early model of the atom and did not survive further experimental scrutiny of the structure of the atom.

Answer:

Thompsons model

Explanation:

i got it right on the quiz

Answer:

The correct answers are 2, 4

Explanation:

The dispersion of light occurs due to the interaction of electromagnetic radiation with matter, let's analyze the phenomenon, when a ray of light reaches a particle is absorbed and subsequently re-emitted in all directions, for radiation of lower wavelength (higher frequency ) the highest absorptions and therefore the missionary also the highest; An example of this is the blue light from the atmosphere, which is the absorption of blue light and its subsequent re-emission

Based on this explanation, the dispersion in gas particles or molecules is proportional to the frequency of the light (inversely proportional to the wavelength) and is also proportional to the number of dispersing particles in the air, that is, to the total volume of the particles. dispersers.

The correct answers are 2 and 4