What is meant by half life ?

Answers

Answer 1
Half-life is the amount of time it takes a substance to decay half of its original value.

Related Questions

Describe the image with a object distance of 65cm and a focal length of 20cm

Answers

Answer:

Imag distance = 28.9 cm

Explanation:

Given that,

Object distance, u = -65 cm

The focal length of the convex les, f = +20 cm

We need to find the image distance. The lens formula gives the relation between focal length, object distance and image distance is given by :

[tex]\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}\\\\\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}\\\\\dfrac{1}{v}=\dfrac{1}{20}+\dfrac{1}{-65}\\\\v=28.9\ cm[/tex]

So, the image distance is 28.9 cm

The monster wants to make himself known to the family in the cottage in chapters 9-12 of Frankenstein. He decides he can't do that until he masters something. What skill
must he master?
A. How to dress properly
B. Language
C. The rules of etiquette
D. Music

Answers

Answer:

c

Explanation:

Which of the following correctly describes the order of skin layers from the inside to the outside of the body?
A. dermis, epidermis, hypodermis
B. hypodermis, dermis, epidermis
C. epidermis, hypodermis, dermis
D. hypodermis, epidermis, dermis

Answers

Answer:

it is a

Explanation:

dermis,epidermis,hypodermis

Answer:

B. hypodermis, dermis, epidermis

this is because it is inside to outside

hypodermis is deeper tissue, dermis is beneath epidermis, and epidermis is the outermost layer

A force F making an angle with the horizontal is acting on an object resting on the table. Which statement is true for the motion of sliding the object on the table? A. It is independent of all the forces acting on the object. B. It depends only on the forces acting along the x-axis. C. It depends only on the forces acting along the y-axis. D. It depends only on the normal force acting on the object. E. It depends only on the frictional force acting on the object.

Answers

Answer:

C

Explanation:

it depends only on the forces acting along the y- axis

Answer:

The statement that is true for the motion of sliding the object on the table is : its independent of all forces acting on the object

Explanation:

A wave is traveling at a speed of 12m/s and its wavelength is 3 m calculate the wave frequency

Answers

Answer:

f = 4 Hz

Explanation:

Given that,

The speed of a wave, v = 12 m/s

The wavelength of a wave, [tex]\lambda=3\ m[/tex]

We need to find the frequency of the wave. We know that the speed of wave is equal to the product of wavelength and frequency. So,

[tex]v=f\lambda\\\\f=\dfrac{v}{\lambda}\\\\f=\dfrac{12}{3}\\\\f=4\ Hz[/tex]

So, the frequency of the wave is equal to 4 Hz.

how to prepare a trading stock account​

Answers

Answer:

Opening stock details of raw material, semi-finished goods and finished goods.

Closing stock details of raw material, semi-finished goods, and finished goods.

Total purchases of goods fewer Purchase Returns.

Total sales of goods fewer Sales Returns.

A coil of 27 turns is in the shape of an ellipse having a major axis of 12.0 cm and a minor axis of 9.00 cm. The coil rotates at 57rpm in a region in which the Earth's magnetic field is 74.0 microT. What is the maximum voltage induced in the coil if the axis of rotation of the coil is along its major axis and this axis of rotation is aligned perpendicular to the Earth's magnetic field

Answers

Answer:

Explanation:

Emf induced e = nBAω sinωt where n is no of turns , B is magnetic field, A is area of the coil ω is angular frequency of rotation .

maximum emf =  nBAω

Given n = 27 , B = 74 x 10⁻⁶ T , A = .12 m x .09 m = 108 x 10⁻⁴ m²

ω = 2π x 57/60 = 5.966 rad/s .

Putting the values

maximum emf  = 27 x 74 x 10⁻⁶ T x 108 x 10⁻⁴ m² x 5.966 rad/s .

= 1.29 x 10⁻⁴ V  .

What is the meaning of the density of states function?

Answers

Ans-The density of states function describes the number of states that are available in a system and is essential for determining the carrier concentrations and energy distributions of carriers within a semiconductor.

Answer:

density equal to mass upon volume

simple definition

state the property of plastic that allows it to become electrostatically charged
(please answers ty) ​

Answers

Answer:

when a plastic rod is rubbed with a duster, electrons are transferred from one material to the other. The material that gains electrons becomes negatively charged. The material that loses electrons becomes positively charged.

How important do you think temperature, radiation, and geologic activity are to the habitability in general?

Answers

Answer:

Explanation:

All 3 are critical for habitability

A satellite is a large distance from a planet, and the gravitational force from the planet is the only significant force exerted on the satellite. The satellite begins falling toward the planet, eventually colliding with the surface of the planet. As the satellite falls, what claims is correct about how the force that the planet exerts on the satellite Fps changes and how the force that the satellite exerts on the planet Fsp changes, if at all? What reasoning supports this claim?

Answers

Answer:

The answer is "Option A".

Explanation:

Please find the complete question in the attached file.

The strength is equal due to the third law of Newton, and [tex]Fsp = Fps = \frac{Gmsmp}{r^2}\[/tex], therefore the force increases with decreased separation r.

A single movable pulley is used to lift 4000N load to the height of 50 cm. If the efficiency of the pulley is 75%, Calculate effort distance,effort applied,output work and mechanical advantage.

Answers

Since the efficiency of the pulley is 75% and the single movable pulley is used to lift 4000N load to the height of 50 cm, the effort distance, effort applied, output work and mechanical advantage are as follows:

Effort Distance = 50 cm

Effort Applied = 5333.33 N

Output work = 2000 J

Mechanical Advantage = 0.75.

When a single movable pulley is used to lift a load, the effort applied is equal to the weight of the load being lifted, and the effort distance is the distance the effort is applied.

Load (output force) = 4000 N

Height lifted = 50 cm = 0.5 m

Efficiency of the pulley = 75%

Given the above information, we can calculate the effort applied, output work, and mechanical advantage as follows:

Effort applied (input force) = Load ÷ Efficiency

= 4000 N ÷ 0.75

= 5333.33 N

Output work = Load x Height lifted

= 4000 N x 0.5 m

= 2000 J

Effort distance = Height lifted

= 50 cm

Mechanical advantage = Load ÷ Effort applied

= 4000 N ÷ 5333.33 N

= 0.75

It is worth noting that pulley efficiency is the ratio of output work to the input work. And since the efficiency of the pulley is 75% so the input work is greater than the output work, which means some of the energy is wasted in overcoming friction and other losses.

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Please need help ASAP, ASAP

Answers

If force is doubled, acceleration will also be doubled.

Newton’s second law of motion, unlike the first law of motion, pertains to the behaviour of objects for which all existing forces are unbalanced. The second law of motion is more quantitative and is used extensively to calculate what happens in situations involving a force.It states that: Force is equal to the rate of change of momentum. For a constant mass, force equals mass times acceleration.The acceleration of the body is directly proportional to the net force acting on the body and inversely proportional to the mass of the body. This means that as the force acting upon an object is increased, the acceleration of the object is increased.

In this given question, force is doubled. We know that force is directly proportional to acceleration. As we increase the force on an object the acceleration increases proportionally. Therefore, if you double the force you double the acceleration.

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a mango fruit drop down from top of its tree which is 5m high. How long does it take to reach the ground​

Answers

Answer:

What is the mass tho?

You need the mass to answer this question

Answer:

[tex]distance = ut + \frac{1}{2} g {t}^{2} \\since \: the \: fruit \: is \: from \: rest : \: initial \: velocity \: is \: 0 \: (u = 0) \\ 5 = (0 \times t) + ( \frac{1}{2} \times 9.81 \times {t}^{2} ) \\ 5 = 4.905 {t}^{2} \\ t = \sqrt{1.0194} \\ t = 1 \: second[/tex]

How far from the earth must a body be along a line toward the sun so that the sun’s
gravitational pull balances the earth’s? The sun is 9.3 × 107 miles away and its mass is
3.24 × 105 Me.

Answers

Answer:

r = 1.63×10^5 mi

Explanation:

Let r = distance of object from earth

Rs = distance between earth and sun

Ms = mass of the sun

= 3.24×10^5 Me (Me = mass of earth)

At a distance R from earth, the force Fs exerted by the sun on the object is equal to the force Fe exerted by the earth on the object. Using Newton's universal law of gravitation,

Fs = Fe

GmMs/(Rs - r)^2 = GmMe/r^2

This simplifies to

Ms/(Rs - r)^2 = Me/r^2

(3.24×10^5 Me)/(Rs - r)^2 = Me/r^2

Taking the reciprocal and then its square root, this simplifies further to

Rs - r = (569.2)r ----> Rs = 570.2r

or

r = Rs/570.2 = (9.3×10^7 mi)/570.2

= 1.63×10^5 mi

The planet Mars has a mass that is 0.11 times Earth’s mass and a radius that is
0.54 times Earth’s radius. a) How much would a 60.0-kg astronaut weigh if
she were to stand on the surface of Mars?

Answers

The weight of an object is a measure of the force of gravity acting on that object. The force of gravity is proportional to the mass of the object and inversely proportional to the square of the distance between the object and the center of the gravitational field.

Since the mass of Mars is 0.11 times the mass of Earth and the radius of Mars is 0.54 times the radius of Earth, the gravitational field on Mars is weaker than the gravitational field on Earth. To calculate the weight of the astronaut on Mars, we need to use the formula for gravitational force:

F = G * m1 * m2 / r^2

where F is the gravitational force, G is the gravitational constant, m1 is the mass of the object being attracted, m2 is the mass of the object providing the gravitational field, and r is the distance between the two objects.

Since the mass of the astronaut is m1 and the mass of Mars is m2, we can plug these values into the formula to find the gravitational force on the astronaut on Mars:

F = (6.67 x 10^-11 N*m^2/kg^2) * (60.0 kg) * (0.11 * 5.97 x 10^24 kg) / (0.54 * 6.371 x 10^6 m)^2

Solving this equation, we find that the weight of the astronaut on Mars is approximately 44.4 N, or about 44.4% of her weight on Earth.

When a body is accelerated under water, some of the surrounding water is also accelerated. This makes the body appear to have a larger mass than it actually has. For a sphere at rest this added mass is equal to the mass of one half of the displaced water. Calculate the force necessary to accelerate a 10 kg, 300-mm-diameter sphere which is at rest under water at the acceleration rate of 10 m/s2 in the horizontal direction. Use H2O

Answers

Solution :

Mass of the sphere, m = 10 kg

Diameter, D = 300 mm = 0.3 m

Volume of the sphere is [tex]$V=\frac{4}{3} \pi \left(\frac{0.3}{2}\right)^3$[/tex]

                                       [tex]$V=0.01414 \ m^3$[/tex]

So the volume of displaced water, [tex]$V_w=V = 0.01414 \ m^3$[/tex]

Additional mass, [tex]$m_w = \frac{1}{2} \ \rho_w\times v_w$[/tex]

                                  [tex]$=\frac{1}{2} \times 1000 \times 0.01414$[/tex]

                                  [tex]$=7.0686 \ kg$[/tex]

So the total mass, [tex]$M = m_w+m$[/tex]

                                   = 7.0686 + 10

                                   = 17.0686

Force required, F = Ma

[tex]$F=17.0686 \times 10$[/tex]

   = 170.686 N

The force that is necessary to accelerate when the acceleration rate of 10 m/s2 in the horizontal direction should be 170.686 N.

How to calculate the force?

Since Mass of the sphere, m = 10 kg

Diameter, D = 300 mm = 0.3 m

Now volume of the sphere is

V = 4/π (diameter/3)^3

V = 4/3π(0.3/2)^3

= 0.01414m^3

Now the additional mass is

= 1/2* 1000 * volume

= 1/2 *1000*0.01414

= 7.0686

So, the total mass is

= Additional mass + force

= 7.0686 + 10

= 17.0686

Now the force is

= 17.0686 * 10

= 170.686

Hence, The force that is necessary to accelerate when the acceleration rate of 10 m/s2 in the horizontal direction should be 170.686 N.

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True or False? 13. All living things are made of cells 14. All cells have DNA within their nucleus 15. The cell is the basic unit of life in all organisms 16. All cells in a living thing are similar in structure or function 17. Cells must develop from other cells

Answers

Answer:

1: True

2: False

3: True

4: False

5: True

Two engines create SIL values of 75 dB and 85 dB respectively. What dB reading would you expect when both are run simultaneously?

Answers

Answer:

Explanation:

In a quiet forest, you can sometimes hear a single leaf fall to the ground. ... greater its pressure amplitude, the more the air is compressed in the sound it creates. ... Graphs of the gauge pressures in two sound waves of different intensities. ... The sound intensity level β in decibels of a sound having an intensity I in watts per .

A 30-g bullet traveling horizontally at 300 m/s strikes a 1.0-kg block which is attached to a horizontal spring with a force constant of 2000 N/m and rests on a frictionless horizontal surface. The spring is on the far side of the block and aligned with the direction of travel of the bullet. The bullet becomes embedded in the block and, as a result of the impact, and the block slides against the spring. How far is the spring compressed before it reverses its direction of travel

Answers

Answer:

Explanation:

Using law of conservation of momentum during collision , velocity after collision can be found .

common velocity V = m v / ( m + M )

= .030 x 300 / ( .030 + 1 )

V= 8.7378 m /s

The kinetic energy of the bullet and block will be stored as elastic energy

1/2 ( M + m ) V² = 1/2 k A² where k is force constant and A is maximum compression in the spring .

( M + m ) V² =  k A²

1.030 x 8.7378² = 2000 x A²

A² = .0393

A= .1982 m .

= 19.82 cm

True or False question! ⬇⬇ Will give BRAINLIEST!
No matter the medium, light will always bend at the same angle when it passes from one medium to a different medium.
-True
-False

Answers

Answer:

the answer can be probably true since light can be refracted

The momentum of an object is determined to be 7.2×10-3 kg⋅m/s. Express this quantity as provided or use any equivalent unit. (Note: 1 kg = 1000 g

Answers

The mass of the moving item is referred to as momentum. There is magnitude and direction to momentum. The object has a momentum of 7.2 g-m/s.

What is the momentum of an object?

Momentum is a vector quantity that is created during motion by an object's mass and velocity. Thus, momentum will be expressed in units of kg-m/s.

Considering that item has motion. Likewise, 1 kilogram equals 1000 g. Therefore, the momentum will transform into units of grams when we enter the value of 1 kg.

Momentum = 7.2 x 10⁻³ 1000g-m/s

Momentum = 7.2 g-m/s.

Thus, we may deduce that the object's momentum, measured in grams per second, is 7.2 g-m/s.

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A gas is placed in a 5.0-mL syringe. It exerts 141 mm Hg of pressure on the inside walls of the syringe. The syringe's plunger is pressed, reducing the volume of the syringe to 2.9 mL. The cap was not removed from the syringe, so none of the gas escapes. Assuming the temperature of the gas does not change, use Boyle's law (below) to determine the pressure of the compressed gas. P_1V_1 = P_2V_2

Answers

Answer: [tex]243.10\ mm\ \text{of}\ Hg[/tex]

Explanation:

Given

The initial volume of gas [tex]V_1=5\ ml[/tex]

Initial pressure is [tex]P_1=141\ mm\ \text{of}\ Hg[/tex]

Final volume is [tex]V_2=2.9\ ml[/tex]

As it is given [tex]P_1V_1=P_2V_2[/tex]

insert the values

[tex]141\times 5=P_2\cdot 2.9\\P_2=243.10\ mm\ \text{of}\ Hg[/tex]

define area and give its SI unit

Answers

Answer:

area is the space bounded by certain lines, the SI unit of area is m²

area of rectangle =l×w×h

square=l²

What are the horizontal and vertical components of a cat's displacement when the cat has climbed 5 m
directly up a tree © = 90°? Sin90=1
cos90=0

Answers

The horizontal component of the cat's displacement, Dx = 0 m

The vertical component of the cat's displacement, Dy = 12 m

What are the horizontal and vertical components of a vector?

The horizontal component of a vector is the value of that vector acting in the horizontal direction.

The horizontal component of a vector is given as Dx.

Dx = Dcosθ

where;

D is the resultant of the vector

θ is the angle of the vector from the horizontal

The horizontal component of the cat's displacement is:

Dx = 12 * 0

Dx = 0 m

The vertical component of a vector is the value of that vector acting in the vertical direction.

The vertical component of a vector is given as Dy.

Dy = Dsinθ

where;

D is the resultant of the vector

θ is the angle of the vector from the horizontal

The vertical component of the cat's displacement is:

Dy = 12 * 1

Dy = 12 m

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Sound is not so distinct at day due to............​

Answers

Explanation:

This is because of a phenomenon called refraction which effects the direction of sound.

Three point charges q1 = +2 μC, q2 = −3 μC, and q3 = +4 μC are located at the corners of a right angle triangle as shown below. Find the magnitude and direction of the resultant force on q3.

Answers

Answer:

Explanation:

4

The magnitude and direction of the resultant force on q3 is;

F_net = 32.2 N in the direction of q3

We are given;

q1 = +2 μC = 2 × 10^(-6) C

q2 = -3 μC = -3 × 10^(-6) C

q3 = +4 μC = 4 × 10^(-6) C

Now,from the given image, charges q1 and q2 attract charge q3.

Formula for force on a charge is;

F = (kq1 * q2)/r²

Where;

k = 9 × 10^(9) N.m²/C²

Thus;

F_y = kq1*q3/(r1)²

We have;

q1 = 2 × 10^(-6) C

r1 = 5 cm = 0.05 m

q3 = 4 × 10^(-6) C

Thus;

F_y = (9 × 10^(9) × 2 × 10^(-6) × 4 × 10^(-6))/(0.05^(2))

F_y = 28.8 N

Similarly;

F_x = kq2*q3/(r2)²

r2 = 5/(tan 30)

r2 = 8.66 cm = 0.0866 m

F_x = (9 × 10^(9) × -3 × 10^(-6) × 4 × 10^(-6))/(0.0866^(2))

F_x = -14.4 N

Thus, magnitude of resultant force is;

F_net = √((28.8)² + (-14.4)²)

F_net = √1,036.8

F_net = 32.2 N

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Net work W would accelerate an object from rest to velocity v. What net work is needed to accelerate the object from rest to velocity 2v?

Answers

The net work that is needed to accelerate a 2.0 kg mass from rest to velocity 2v is 4.0 m/s.

What is net work done?

When a force acts on a body at rest or at uniform motion in a straight line, then it starts to accelerate.

Given that, the velocity is 5.0

Time is 2 sec

The given mass is 2.0 kg

First, we calculate the acceleration

Acceleration = v / t = 10 / 5.0 = 2

From Newton's second law, we know that

force = mass x acceleration

F = ma

F = 2.0 x 2 = 4.0 m/s

Therefore, the net work that is needed to accelerate a 2.0 kg mass from rest to velocity 2v is 4.0 m/s.

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The question is incomplete. Your most probably complete question is given below:

What net force is needed to accelerate a 2.0 kg mass from rest to a velocity of 10 m/s in 5.0 s?

4. How many excess electrons does a balloon that was rubbed on a child's hair and
now has a charge of 4.0 x 107 Coulombs?

Answers

The number of excess electrons in a balloon with a charge of 4.0 x 107 Coulombs is 4.0 x 10^7 electrons.

Hope this helps!

In velocity time graph of a body, two points are given as A(40,5) and B(20,2). What is the acceleration of the body

Answers

Answer:

0.15 m/s²

Explanation:

Acceleration is rate of change of velocity-time function. We can find acceleration by finding the slope. The slope of graph can be found by:

[tex] \displaystyle{a = \dfrac{ \Delta v}{ \Delta t} \: \to \: \dfrac{v_f - v_i}{t_f- t_i}}[/tex]

Substitute in:

[tex] \displaystyle{a = \dfrac{5 - 2}{40 - 20}} \\ \\ \displaystyle{a = \dfrac{3}{20}} \\ \\ \displaystyle{a = 0.15 \: \text{m/s}^{2} }[/tex]

Therefore, the acceleration is 0.15 m/s²

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