1. A television set falls from rest from a bridge 100m above the river surface.

Răspuns:

7: 4

Explicaţie:

Formula pentru calcularea cantității de căldură absorbită este exprimată ca;

Q = mc∆t

m este masa substanței

c este capacitatea termică specifică

∆t este schimbarea temperaturii

Conform legii calorimetriei, căldura pierdută de substanța rece = căldura câștigată de substanța fierbinte.

Folosind formula

(mc∆t) rece = (mc∆t) fierbinte

McCw∆tc = MhCw∆th

Deoarece au aceeași capacitate de căldură specifică, se vor anula. Ecuația devine;

Mc∆tc = Mh∆th ...... 1

Pentru apa rece;

∆tc = 45 ° C - 10 ° C

∆tc = 35 ° C

Pentru apa fierbinte:

∆th = 65 ° C - 45 ° C

∆th = 20 ° C

Înlocuiți în ecuația 1;

Mc (35) = Mh (20)

35Mc = 20Mh

Luând raportul dintre masa apei reci și cea fierbinte:

Mh / Mc = 35/20

Mh / Mc = 7/4

Prin urmare, lichidul trebuie amestecat împreună în raportul 7: 4

Answer:

Explanation:

According to Newton's second law of lmotion

Force = mass × acceleration

Given

Mass = 1kg

Force = 2N

Required

Acceleration of the 2N body

From the formula

Acceleration = Force/mass

Acceleration = 2N/1

Acceleration = 2m/s²

Answer:

(a) La aceleración de la gravedad en esa órbita es 0.22 [tex]\frac{m}{s^{2} }[/tex]

(b) Un satélite de 1,200 kg pesará allí 264 N.

Explanation:

(a) Cada punto del espacio tiene un  valor del campo proporcional a la función, siguiendo el modelo de gravitación de Newton:

[tex]g=G*\frac{m}{r^{2} }[/tex]

donde m será masa, r  la distancia entre los objetos y G la constante de gravitación universal, cuyo valor es [tex]G=6.672*10^{-11}\frac{N*m^{2} }{kg }[/tex]

En este caso:

Reemplazando:

[tex]g=6.672*10^{-11}\frac{N*m^{2} }{kg }*\frac{6*10^{24}kg }{(42,370,000 m)^{2} }[/tex]

Resolviendo, obtenes:

g= 0.22 [tex]\frac{m}{s^{2} }[/tex]

La aceleración de la gravedad en esa órbita es 0.22 [tex]\frac{m}{s^{2} }[/tex]

(b) La ley fundamental de la dinámica o segunda ley de Newton expresa que la fuerza neta que es aplicada sobre un cuerpo es proporcional a la aceleración que adquiere en su trayectoria.  Esto se expresa matemáticamente como:

F= m*a

en donde  F es fuerza neta , m la masa y a la aceleración.

El peso es la fuerza que ejerce la gravedad sobre una masa, por lo que se obtiene de manera análoga a la fuerza:

P=m*g

En este caso la masa m tiene un valor de 1,200 kg y la gravedad g un valor de 0.22 [tex]\frac{m}{s^{2} }[/tex].

Reemplazando:

P=1,200 kg*0.22 [tex]\frac{m}{s^{2} }[/tex]

Resolviendo:

P= 264 N

Un satélite de 1,200 kg pesará allí 264 N.

Answer:

The Bt gene is inserted into one plant cell by using a bacterial plasmid.

Explanation:

Answer:

B.

Velocity describes how fast something is going, whereas Speed describes how fast something is going and in which direction.

Explanation:

. If the above statement is true, then describe an example of such a motion. ... b. What was the displacement for the entire trip? 0 miles (You finish where you started) ... Speed is a quantity that describes how fast or how slow an object is moving.

Answer:

2.At the end of meiosis, there are four cells each with 23 chromosomes, for a total of 92 chromosomes split between the four cells.

Answer:

In a discharging battery or galvanic cell (diagram at right), the anode is the negative terminal because it is where conventional current flows into the cell.

Explanation

In the lab. construct two half cells, one a zinc half cell and the other a copper half cell.

The zinc metal electrode will more readily ionise to Zn^2+  ion , then the copper metal.

This is because in the reactivity series zinc is more reactive metal.

Hence

connecting the two half cells, the zinc cell is put on the left and the copper half cell on the right.

Connect a wire and voltmeters between the electrodes, and a salt bridge between the two metal ion solutions.

Since the zinc is on the left and loses its electrons more readily the electrons flow from the electrode through the wire and voltmeter to the copper electrode.  So the electrons flow from r

left to right.

The conventional eq'n is

Zn|Zn^2+||Cu^2+|Cu

The electrons move into the copper electrode combine with copper solution to form more copper metal, which deposits on the copper electrode.

In a battery (voltaic cell), conventional current flow in the direction from positive to negative.

Current is a flow of charges. it is denoted by i and expressed in ampere A.

Mathematically it is expressed as i = q/t, where q is the amount of charge and t is time. Current is nothing but amount of charges flown in the unit time in the electric wire. Charge is expressed in coulomb C and time in second s. hence coulomb per second (C/s) is ampere A. Charge on electron is 1.60217663 × 10⁻¹⁹ which is called as elementary charge.

There are two types of the current, Convectional current and non-conventional current.

Convectional current is the current flows from positive to negative. Non convectional current flows from negative to positive. Note that flow of electrons is from negative to positive.

Hence direction of flow of conventional current is from positive to negative.

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Answer:

Explanation:

The mass of the object can be found by using the formula

[tex]m = \frac{f}{a} \\ [/tex]

f is the force

a is the acceleration

From the question we have

[tex]m = \frac{147}{9.8} \\ [/tex]

We have the final answer as

Hope this helps you

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[tex] {v}^{2} - {v(0)}^{2} = 2.a.∆x[/tex]

[tex]v = final \: \: velocity[/tex]

[tex]v(0) = the \: \: velocity \: \: in \: \: the \: \: rest \: \: which \: \: is \: \: zero \\ [/tex]

[tex]a = acceleration[/tex]

[tex]∆x = covered \: \: distance[/tex]

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[tex] {v}^{2} - ({0})^{2} = 2 \times 26 \times 402 [/tex]

[tex] v = \sqrt{2 \times 26 \times 402} [/tex]

[tex]v = \sqrt{20904} [/tex]

[tex]v = 144.58 \: \: \frac{m}{s} [/tex]

Done...

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Answer:

a &c

Explanation:

>3

Attraction between the molecules of a liquid and the temperature at which the liquid changes state is "Strong attractions mean the liquid boils at a higher temperature". The correct option is C

Temperature is a physical quantity which measures hotness and coldness of a body. Temperature measures the degree of vibration of molecule in a body. Temperature is measured in centigrade (°C), Fahrenheit (°F) and Kelvin (K) in which Kelvin (K) is a SI unit of temperature. Absolute scale of temperature means Kelvin scale of temperature.

relation between Kelvin(K) and centigrade (°C),

°C= K - 273.15

from equation, 273.15 K means 0 °C, which is freezing point of water (ice).

when we give temperature to the body, its molecule or atom absorbs thermal energy and vibrate about their mean position. Amplitude of vibration get increases as we go on increasing temperature and for higher temperature force of attraction between molecules gets weaker. Hence for higher temperature, due to weaken the force of attraction between molecule, solid goes into liquid state. and further increase in temperature liquid goes into gaseous state.

Liquid has stronger force of attraction than gas and weaker than solid. Strong force of attraction means high temperature should be given to break molecular bonds. Therefore Strong attractions mean the liquid boils at a higher temperature.

Hence option C is correct.

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Answer:

top to 2\

next to top

then to up one

next to up

Explanation:

Explanation:

distance

speed =_________

time

distance = speed × time

= 2.5 × 5.0

distance = 12.5 m

Answer:

I'm terrible at explaining so here's a screenshot, please do not listen to the other answer, it is wrong.

- Ripper

Explanation:

Answer:

C is the correct answer !!!

Explanation:

Answer:

a

Explanation:

a

Answer:

False

Explanation:

You get more kinetic energy the more the particles and less kinetic energy with less particles

Answer:

Explanation:

The sandpaper block did not move because the forces of friction and gravity were balanced.

Answer:

False

True

False

True

False

True

Explanation:

Answer:

A E and F are the correct answers

Explanation:

Answer:

A E F are correct

Explanation:

Answer : 16 m/s east

Explanation: Trust the process!!

From the frame of reference of runner 1, the velocity of runner 2 will be D) 16 m/s east

The relative velocity is defined as the velocity of an object with respect to another observer

When two bodies are moving in opposite directions , relative velocity get added and if bodies are moving in same direction , relative velocity will get subtracted .

From the frame of reference of runner 1, the velocity of runner 2 will be

v (relative) = v1 + v1

v1 = velocity of runner 1  = 11m/s west

v2 = velocity of runner 2 = 5m/s

v = 11 + 5 = 16 m/s

correct answer will be O D. 16 m/s east as runner 2 is running in east direction

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Answer:

D

Explanation:

It does all three

Answer:

negative ion

Explanation:

An atom that has fewer neutrons than protons and more electrons than protons is a negative ion.

The positively charged particles in an atom are the protons

The negatively charged particles in an atom are the electrons.

  The charge an atom carries depends on the balance between the number of protons and electrons in an atom.

negative ion

Explanation:

An atom that has fewer neutrons than protons and more electrons than protons is a negative ion.

The positively charged particles in an atom are the protons

The negatively charged particles in an atom are the electrons.

 The charge an atom carries depends on the balance between the number of protons and electrons in an atom.

When the number of protons is more than the number of electrons, the atom is positively charged.

When the number of electrons is more than the number of protons, the atom is negatively charged.

Answer:

B

Explanation:

This is a balanced force. In a balanced force, nothing happens.

Answer:

All i got to say is that he is dead dead

Explanation:

Answer:

Heat of vaporization

Explanation:

When water is at high levels of temperature heat is move as an energy source into the air.    

Answer:

[tex]\boxed {\boxed {\sf Heat \ of \ vaporization}}[/tex]

Explanation:

There are two options for this answer: heat of fusion or heat of vaporization.

Let's define both of the terms.

Heat of fusion:

Heat of vaporization:

The question asks us which type of heat provides the energy for the phase change of a liquid to a gas. Therefore, the correct answer is heat of vaporization.

Answer:

11196.14 m

Explanation:

From the question given above, the following data were obtained:

Horizontal velocity (u) = 286.2 m/s

Height (h) = 7500 m

Horizontal distance (s) =?

Next, we shall determine the time taken for the payload to get to the target. This can be obtained as follow:

Height (h) = 7500 m

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =?

h = ½gt²

7500 = ½ × 9.8 × t²

7500 = 4.9 × t²

Divide both side by 4.9

t² = 7500 / 4.9

Take the square root of both side

t = √(7500 / 4.9)

t = 39.12 s

Finally, we shall determine the horizontal distance as follow:

Horizontal velocity (u) = 286.2 m/s

Time (t) = 39.12 s

Horizontal distance (s) =.?

s = ut

s = 286.2 × 39.12

s = 11196.14 m

Thus the payload will travel 11196.14 m horizontally in order to hit the target

The combination of a wire coil and a core would make the weakest electromagnet 20 coils of insulated wire around a hollow cardboard core. Thus, option B is correct.

Electromagnet is a type of magnet that produces its magnetic field when an electric field is applied across the material. The electromagnet is the temporary magnet as it acquires the magnetic properties when the electric current passes through it. When there is no electric current, its magnetic properties disappear.

Electromagnet consists of a wire wound on the coil and the current passes through the wire. The wire wound on the coil is mostly a ferromagnetic material like iron and the coil is a soft iron core. In an electromagnet, the magnetic field depends on the number of turns of the coil and the current flows through it.

From the given, steel core is wounded with wire it makes a strong electromagnet depending on the number of turns of the coil. The cardboard core is not a ferromagnetic material and hence, a small number of turns over the cardboard forms the weakest electromagnet.

Hence, the ideal solution is option B)20 coils of insulated wire around a hollow cardboard core.

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Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 75 × 35

We have the final answer as

Hope this helps you