Please help ..... 10 points .....

Answer:

The half-life of a radioactive isotope is the time such that the initial amount of the isotope is reduced to its half.

Thus, if we start with A grams of a given radioactive isotope, after a 1 half-life, we will have A/2 grams of the radioactive isotope.

In this case, we know that the sample has 110g of a radioactive isotope.

Then, after 1 half-life, we should have half of 110g, which is:

110g/2 = 55g

Then we should have 55 g of a radioactive isotope.

The answer that is closer to this result is option d (50 g), so that is the correct one.

Answer:

P = 106.7 W

Explanation:

Given that,

Work done in lifting a backpack, W = 80 J

It is lifted in 0.75 seconds

We need to find the power of the student. The power of an object is defined as work done per unit time. So,

[tex]P=\dfrac{W}{t}[/tex]

Put all the values,

[tex]P=\dfrac{80}{0.75}\\\\P=106.7\ W[/tex]

So, the power of the student is 106.7 W.

Answer:

20 m/s

Explanation:

Look at the time on the x-axis. Go up from 2 seconds until you reach a point. From that point go to the left and read from the y-axis.

The statement did Ernest Rutherford make about atoms will be the atom has a small, dense center. Then the correct option is B.

The majority of alpha particles went right through the gold foil, signifying that particles are mostly made up of empty space. Several alpha particles were mildly distracted, indicating interactions with positively charged particles within the unit. Some alpha particles were spread at wide degrees, with a few even returning to the source.

Rutherford characterized the atom in 1911 as having an understanding, dense, and ionized center termed the nucleus. Rutherford discovered that the mass of an atom is possessed in its nucleus.

The atom has a small, dense center. Thus, option B is correct.

More about the Ernest Rutherford model link is given below.

https://brainly.com/question/5831461

#SPJ1

Answer:

It is Limiting Reactant

Explanation:

Answer:

La mayoría de los adultos necesitan entre 7 y 8 horas de sueño de buena calidad en un horario uniforme todas las noches.

Explanation:

Answer:D.

Real, inverted, smaller than the object, and closer to the mirror than the object

Explanation: Real images will be inverted. As it is beyond the centre of curvature it is also beyond 2F which means that the image is inside the centre of curvature ( between F and 2F from the mirror ) As the image is closer to the mirror than the object it must be diminished in size

Answer:

The thermal energy gained by the water during the entire process is 90,372 J

Explanation:

Given;

mass of the ice cube, m = 30 g

latent heat of fusion of ice, L = 334 J/g

specific heat capacity of water, C = 4.184 J/g⁰C

latent heat of vaporization of water, h = 2260 J/g

The thermal energy gained by the water during the entire process is calculated as;

[tex]Q_t = Q_{fusion-ice} \ + \ Q_{boil-water} \ + \ Q_{steam-vapor}[/tex]

The heat of fusion of the ice at 0⁰C is calculated as;

[tex]Q_{fusion} = mL = 30\ g \times 334 J/g = 10020 \ J[/tex]

The heat of capacity of the water from  0⁰C to 100 ⁰C

[tex]Q_{boil-water} = mc\Delta \theta = mc(100-0) = 30\ g \times 4.184\ J/g^0C \times 100\ ^0C = 12,552 \ J[/tex]

The heat of vaporization of the steam at 100⁰C is calculated as;

[tex]Q_{steam} = mh= 30 g \times 2260 \ J/g= 67,800 \ J[/tex]

The thermal energy gained by the water during the entire procees;

Qt = 10,020 J  +  12,552 J   +  67,800 J

     = 90,372 J

Therefore, the thermal energy gained by the water during the entire process is 90,372 J

Answer:

The correct answer is C I took the mastery test

Explanation:

Answer:

d last one

Explanation:

Answer:

C

Explanation:

Answer:

c

Explanation:

edge

Answer: Bedrock

Explanation:

Bedrock is the solid layer of rock beneath the soil. Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. The decayed organic material in soil is humus, a dark-colored substance that forms as plant and animal remains decay.

Answer:

The appropriate solution is "61.37 s".

Explanation:

The given values are:

Boat moves,

= 10 m/s

Water flowing,

= 1.50 m/s

Displacement,

d = 300 m

Now,

The boat is travelling,

= [tex]10+1.50[/tex]

= [tex]11.5 \ m/s[/tex]

Travelling such distance for 300 m will be:

⇒ [tex]v = \frac{d}{t} \ sot \ t[/tex]

      [tex]=\frac{d}{v}[/tex]

On putting the values, we get

      [tex]=\frac{300}{11.5}[/tex]

      [tex]=26.08 \ s[/tex]

Throughout the opposite direction, when the boat seems to be travelling then,

= [tex]10-1.50[/tex]

= [tex]8.5 \ m/s[/tex]

Travelling such distance for 300 m will be:

⇒ [tex]v=\frac{v}{t} \ sot \ t[/tex]

      [tex]=\frac{d}{v}[/tex]

On putting the values, we get

      [tex]=\frac{300}{8.5}[/tex]

      [tex]=35.29 \ s[/tex]

hence,

The time taken by the boat will be:

= [tex]26.08+35.29[/tex]

= [tex]61.37 \ s[/tex]

Answer:

Oxide

Explanation:

Ozone and oxygen are oxidising agents

[tex]O _{3} \: \: ozone \\ \\ O _{2} \: \: oxygen[/tex]

Answer:

Oxygen

Explanation:

The name oxidation actually originates from the word oxygen so the question answers it's self.

In case you don't know what oxidation is:

Oxidation occurs when an atom, molecule, or ion loses one or more electrons in a chemical reaction. When oxidation occurs, the oxidation state of the chemical species increases. Oxidation doesn't necessarily involve oxygen! Originally, the term was used when oxygen caused electron loss in a reaction.

Have a great day <3

Answer:

A. 1.78 m

Explanation:

Given;

initial velocity of the, u = 12 m/s

angle of projection, θ =  30°

the range of the projectile, R = 7.5 m

To obtain the height through which the projectile lands, we must calculate the maximum height reached by the projectile.

[tex]H = \frac{u^2\ sin^2\theta}{2g} \\\\H = \frac{(12)^2\times (sin(30))^2}{2 \times 9.8} \\\\H = \frac{144 \times (0.5)^2}{19.6} \\\\H = 1.84 \ m[/tex]

Therefore, the height is most nearly 1.78 m

Answer:

Following are the responses to the given question:

Explanation:

Following are the difference in the speed and accuracy:

The biggest difference was its tone between both the cup method as well as the Morse code. One should talk using cup system and sequence system and let its covering be understood in Morse code, just a series of beeps weren’t tangible... Secondly, a method of cup involves a range string. Rukun Negara is often distributed by cable, but this is a greater range. It reaches concurrently in those other areas.

In the case of using the string method for the block, its distance and stiffness of the string are limited and the barriers are eliminated. It will certainly be convenient and clearer if one utilizes Sign language.

If two experts are acting like such a machine on both sides, their information between both the 2 persons is smoother and quicker as they will not have to wait for data from a third person which may create another pause at the time.

Morse code is faster, eventually. For some very small periods when sensitive information is not transmitted, strings or cup methods must be reserved.

Answer:

Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed.

Explanation:

Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The minimum distance in which a sound wave repeats itself is called its wavelength. That is it is the length of one complete wave

Answer: Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed.

Explanation:

The minimum distance in which a sound wave repeats itself is called its wavelength. That is it is the length of one complete wave.

The acceleration of the car must equal zero if a car is moving at a constant rate along a straight line.

A car moving at a constant speed (uniform motion) has all forces acting on it balanced. In this case, the two backward forces (air resistance and friction) perfectly balance the applied force of the wheels on the road in the opposite direction.

Acceleration is defined as the rate of change in speed. So if the car is moving at a constant speed that means the rate of change in speed is zero. Hence, acceleration is zero.

Learn more about acceleration here https://brainly.com/question/14344386

#SPJ2

Answer:

because the Earth rotates, circulating air is deflected. Instead of circulating in a straight pattern, the air deflects toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere, resulting in curved paths. This deflection is called the Coriolis effect.

Answer:

The answer is option C.Half as much

The correct answer is four times as much.

Let the friend's mass be m, then according to the question the bodybuilder's mass will be 2m.

Now they both cover the same distance but the bodybuilder takes 4s and his friend takes 2s. Hence, if the time taken by the friend is t then the bodybuilder takes 2t time.  

That means if the velocity of the bodybuilder is v then the velocity of his friend will be 2v.

Now, Power is defined as the rate of work done.

P = W/t

and work done is the change in kinetic energy.

Now the power generated by the bodybuilder is:

[tex]P_{b}=\frac{\frac{1}{2}2mv^{2} }{2t} \\\\P_b=\frac{mv^2}{2t}[/tex] ............(1)

power generated by the friend is :

[tex]P_{f}=\frac{\frac{1}{2}m(2v)^{2} }{t} \\\\P_b=\frac{4mv^2}{2t}[/tex].............(2)

Comparing (1) and (2) we get:

The friend generates four times as much power as the bodybuilder.

Learn more:

https://brainly.com/question/4232216

Answer:

the answer is (b) Kg ms-1 .

Answer:

The information shows the masses after the compounds are balanced.

2MgO + 2Cl2 → 2MgCl2 + O2

85g + 156g → 188g + 53g

as total mass in reactant is equal to product.

A.

53g of O2, because all mass must be conserved.

Answer:

PLS PLS PLS mark brainliest

Explanation:

The following are the environmental problems caused by the invasive algae which is known as Lyngbya.

A. It blocks the sunlight from reaching the water, thereby depriving the plants in the water from accessing it. So they won't be able to manufacture their foods and eventually die off.

B. The algae produce offensive odour like rotten egg , which drive people and other organisms away.

C. The algae prevent oxygen from entering the water, and prevent the resident organisms from making use of it, which leads to their death.

D. The algae also give off heat into the chilly spring waters.

In conclusion, the goals of the Crystal River project is to save the living organisms in the river from extinction and to make it a livable environment for them.

Answer:

A

Explanation:

Answer: D

Explanation:

Answer:

C. A lob pass.

Hope this helps!!

A)

The moon orbiting the Earth

Answer:

(a) 0.0165 m

(b) 16.5 m

Explanation:

Applying,

v = λf.................. Equation 1

Where v = velocity, f = frequency, λ = wave length.

make λ the subject of the equation

λ = v/f............. Equation 2

(a) Shortest wavelength (λ')

Given: f' = 20000 Hz, v = 330 m/s

Substitute these values into equation 2

λ' = 330/20000

λ' = 0.0165 m

(b) Longest wavelength (λ)

Given: v = 330 m/s, f = 20 Hz

Substitute these value into equation 2

λ = 330/20

λ = 16.5 m

Answer:

35 Joules

Explanation:

Applying

Input Energy(Q) = Useful energy output(U)+Wasted Energy(W)

Q = U+W.............................. Equation 1

Make U the subject of the equation

U = Q-W................... Equation 2

From the question,

Given: Q = 120 Joules, W = 85 Joules

Substitute these values into equation 2

U = 120-85

U = 35 Joules

Answer:

rate

Explanation:

Note that speed has no direction (it is a scalar) and the velocity at any instant is simply the speed value with a direction.

Explanation:

is a formation in space which is constituted mostly of helium, dust and other gases in various concentration