Which of the following happens when a substance melts?

Answer:

True statements a, b, and c

Explanation:

Answer d is false because in any collision, each object receives the same impulse. Also the momentum of car 1 is mv, while the momentum of car 2 is 0.5m(1.5v) = 0.75mv

The impulse of collision of cars depends on the mass and velocity of the cars. The statements which are true about the car collisions are option a, b, c.

Impulse is a physical quantity expressed as the product of force and time. The change in momentum mΔV is numerically equals to the impulse F t.

If two identical cars with identical speeds collide head on, the magnitude of the impulse received by each car and each driver is the same as if one car at the same speed had collided head on with a concrete wall. Because they have equal mass and velocity.

The bigger acceleration is experienced by the one which have lighter mass thus car 1 with lower mass experience higher acceleration .

The essential safety benefit of crumple zones (parts of the front of a car designed to receive maximum deformation during a head-on collision) is due to their absorbing kinetic energy.

Converting this energy into deformation, and lengthening the effective collision time, thus reducing the average force experienced by the driver.

The momentum change is proportional to the velocity. The one which have higher velocity is having the higher momentum. Thus car 2 have higher velocity. Thus option d is false.

Therefore, the statements which are true are a, b and c.

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As we know,

F= ma

Here,

applied force(f)= mass × acceleration

=80kg×3m/s2

=240kgm/s2

=240N

An Excerpt from “Optimism”

by Helen Keller

1 Could we choose our environment, and were desire in human undertakings synonymous with

endowment, all men would, I suppose, be optimists. Certainly most of us regard happiness as

the proper end of all earthly enterprise. The will to be happy animates alike the philosopher, the

prince and the chimney-sweep. No matter how dull, or how mean, or how wise a man is, he feels

that happiness is his indisputable right.

2 It is curious to observe what different ideals of happiness people cherish, and in what singular

places they look for this well-spring of their life. Many look for it in the hoarding of riches, some

in the pride of power, and others in the achievements of art and literature; a few seek it in the

exploration of their own minds, or in the search for knowledge.

3 Most people measure their happiness in terms of physical pleasure and material possession.

Could they win some visible goal which they have set on the horizon, how happy they would be!

Lacking this gift or that circumstance, they would be miserable. If happiness is to be so

measured, I who cannot hear or see have every reason to sit in a corner with folded hands and

weep. If I am happy in spite of my deprivations, if my happiness is so deep that it is a faith, so

thoughtful that it becomes a philosophy of life,—if, in short, I am an optimist, my testimony to

the creed of optimism is worth hearing....

4 Once I knew the depth where no hope was, and darkness lay on the face of all things. Then

love came and set my soul free. Once I knew only darkness and stillness. Now I know hope and

joy. Once I fretted and beat myself against the wall that shut me in. Now I rejoice in the

consciousness that I can think, act and attain heaven. My life was without past or future; death,

the pessimist would say, “a consummation devoutly to be wished.” But a little word from the

fingers of another fell into my hand that clutched at emptiness, and my heart leaped to the

rapture of living. Night fled before the day of thought, and love and joy and hope came up in a

passion of obedience to knowledge. Can anyone who has escaped such captivity, who has felt

the thrill and glory of freedom, be a pessimist?

5 My early experience was thus a leap from bad to good. If I tried, I could not check the

momentum of my first leap out of the dark; to move breast forward is a habit learned suddenly

at that first moment of release and rush into the light. With the first word I used intelligently, I

learned to live, to think, to hope. Darkness cannot shut me in again. I have had a glimpse of the

shore, and can now live by the hope of reaching it.

6 So my optimism is no mild and unreasoning satisfaction. A poet once said I must be happy

because I did not see the bare, cold present, but lived in a beautiful dream. I do live in a

beautiful dream; but that dream is the actual, the present,—not cold, but warm; not bare, but

furnished with a thousand blessings. The very evil which the poet supposed would be a cruel

6) Read the last sentence from the text.

Only by contact with evil could I have learned to feel by contrast the beauty of truth and love and goodness.

Explain how Helen Keller develops this idea in the text. Use specific details to

support your answer.

Answer:

A. scatter plot?

Explanation:

I dont really know if I'm right... sorry.

Answer:

correct answer is A) the height of a wave

Explanation:

i just did the test:)

The amplitude is used represent the height of the wave.

A wave is a disturbance in a medium that carries energy without a net movement of particles. In general, waves are classified into two types as Longitudinal and Transverse

Given is the amplitude of a wave.

Amplitude of a wave is equal to measure of the length of crest or trough. Crest and trough are the points that represents the maximum and minimum displacement of the wave with respect to the reference axis. The crest and the trough points are both at a equal straight line distance from the reference axis. This distance is also called height of the wave. The amplitude is the distance between the centerline and the Crest or trough. The general equation representing the amplitude of wave is x = A sin (ωt + ϕ) or x = A cos (ωt + ϕ) is the formula.

Therefore, the amplitude represents the height of the wave.

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Answer:

sorry I don't know the answer

Answer:

Option A

Explanation:

N is Chloroplast, P is a large centralized vacuole and R is the cell wall which are found only in plant cells. Hence, the given cell is a plant cell.

S = Rough Endoplasmic Reticulum

P = Vacuole

O = Nucleus

T = Smooth Endoplasmic Reticulum

U = Golgi Apparatus

N = Chloroplast

U = Cell Membrane

M = Mitochondria

R = Cell wall

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

(C)

...........................

Answer:

Hope this helps!

Explanation:

Answer:

D) 19.8 lbs

Explanation:

1kg in household measurement is equal to 35.274 ounces. 35.274*9=317.466 ounces.

1kg is also equal to 2.205 lbs. 9*2.205=19.8416

9 kg is also equal to 9000 grams, but grams are not a part of the household measurement system

a) 9000 grams. b) 9000 ounces. c) 19.8 ounces. d) 19.8 pounds.

This leaves us with 19.8 lbs

Answer:  

1N  

Explanation:

Pretty simple Divide 23 by 23 which gives you 1.

23N ÷ 23N = 1N

Answer:

[tex]\sf \longmapsto \: 1 \: N[/tex]

Explanation:

[tex]\sf \longmapsto \frac{23N}{23N} [/tex]

[tex]\sf \longmapsto1 \: N[/tex]

Answer:

Explanation:

My perdiction was correct. I predicted in Part A that the Kinetic Energy would increase. In Part B I predicted that the potential energy would decrease due to the kinetic energy increasing.

Answer:

Water

Explanation:

At 0 degrees it's solid...Then it melts into a liquid and at 100 degrees it's gas Simple

Answer:

If two masses 5.2 kg and 4.8 kg are attached to the ends of inextensible strings passed over a frictionless pulley then the acceleration of system is 0.4 ms-2.

Explanation:

Answer:

Explanation:

Assuming the ground is level as well.

F = ma

a = F/m

a = (2000 - 350) / 1500

a = 1.1 m/s²

The acceleration of the car is 1.1 m/s².

To calculate the magnitude of the acceleration of the car, we use the formula below.

Where:

Make a the subject of the equation

From the equation,

Given:

Substitute these values into equation 2

Hence, the acceleration of the car is 1.1 m/s².

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According to Newton's second law

[tex]\\ \sf\longmapsto Force=Mass\times Acceleration[/tex]

[tex]\\ \sf\longmapsto Mass=\dfrac{Force}{Acceleration}[/tex]

[tex]\\ \sf\longmapsto Acceleration=\dfrac{Force}{Mass}[/tex]

Answer:

Explanation:

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Answer:

2.5 m/s

Explanation:

(60*1.5+60*3.5)/120=2.5

or

(1.5+3.5)/2=2.5

Answer:

Can you rewrite that sorry

Explanation:

Answer:

Explanation:

We are not told what angle the pull rope is to any other reference. That could make a huge difference in the result.

If we ASSUME that the rope pulls parallel to the slope

Then , if T is rope tension

                                  F = ma

T - mgsinθ - μmgcosθ = m(0)

                                 T = mg(sinθ + μcosθ)

                                 T = 40(9.8)(sin14 + 0.15cos14)

                                 T = 151.88677... 150 N

If the rope pulls the sled at a positive angle relative to the slope, As one might expect from an adult holding the rope, then the tension will be increased because only the Tension portion parallel to the slope causes motion in that direction, but will be decreased because the Normal force, and therefore the friction force, of the slope on the sled will be decreased.

Answer:

Aloe, Tulsi, Neem, Turmeric, and Ginger are medicinal plants that can help with a variety of diseases. Ginger, green tea, walnuts, aloe, pepper, and turmeric are just a few of these plants. Some plants and their derivatives are key sources of active compounds used in aspirin and toothpaste, among other things.

Explanation:

Plant name:                                    Uses:

1. Marshmallow:      ////  Relief from aching muscles and pain in muscle, Heals insect bite.             ////

2.California poppy ////  Relieves tension, Removes nervous system

3. Tulsi                ////   Cures sore throat, Cures fever and asthma

4. Neem               ////       Cures skin diseases, Cures diabetics

5. Aloevera      ////             Heals burns, Relieves constipation

(Hope this helps can I pls have brainlist (crown)☺️)

Answer:

D) 19.8 lbs

Explanation:

1kg in household measurement is equal to 35.274 ounces. 35.274*9=317.466 ounces.

1kg is also equal to 2.205 lbs. 9*2.205=19.8416

9 kg is also equal to 9000 grams, but grams are not a part of the household measurement system

a) 9000 grams. b) 9000 ounces. c) 19.8 ounces. d) 19.8 pounds.

This leaves us with 19.8 lbs

Answer:

would it be 2.66666666667 or 2.7

Explanation:

Answer:

Explanation:

Use kinematic equation v² = u² + 2as

Rearrange for distance

s = (v² - u²) / 2a

Realize that at the top of its flight, the ball has zero velocity and gravity is acting downward in an assumed upward positive reference frame.

s = (0² - 29²) / (2(-9.8))

s = 42.90816...

s = 43 m

Answer:

You have to apply more pressure to the pedal so more gas runs through the car allowing it to reach higher speeds

To move, a car or any other object must be accelerated from rest to the desired speed; this necessitates that the engine force be greater than the friction force. The net force must be zero once the car is moving at constant velocity; otherwise, the car will accelerate (gain speed).

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Answer: 39.2m/s

Explanation:

Due to the free falling body, the acceleration of the ball is 9.8 m/s^2, and its initial velocity is 0 m/s.

V(t) = g*t

The change of velocity from t=1 to t=5:

Delta V = 9.8*(5-1) = 39.2 m/s

The definition of average acceleration allows to find the result for the average acceleration in the given time interval is:

          [tex]a_{average}= 1.5 \ \frac{m}{s^2}[/tex]

Instantaneous acceleration is defined as the derivative of velocity with respect to time.

           a =   [tex]\frac{dv}{dt}[/tex]

Where a is the acceleration, v the velocity and t the time.

They indicate that the speed of the car is given by the relation.

          v = α t + β t²

With α = 3 m / s and β = 0.1 m / s³

Let's make  the derivative.

           a = α + 2β t

Let's substitute

            a = 3 + 2 0.1 t

Average acceleration is the change in velocity in the time interval.  

          [tex]a_{average} = \frac{\Delta v}{\Delta t }[/tex]

Let's find the velocity at the indicated time.

For t = 5 s

         v₅ = 3 + 0.1 5²

         v₅ = 5.5 m / s

For t = 10 s

          v₁₀ = 3 + 0.1 10²

          v₁₀ = 13 m / s

Let's calculate the average acceleration.

           [tex]a_{average} = \frac{13 - 5.5 }{ 10 - 5 }\\[/tex]

           [tex]a_{average}= 1.5 \ m/s^2[/tex]

In conclusion using the definition of mean acceleration we can find the result for the mean acceleration in the given time interval is:

           [tex]a_{average} =[/tex]  1.5 m / s²

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