A good soccer player can kick the ball up to 25 m/sec. A soccer ball has a mass of 800 grams (0.8 kg). What force must a goalie exert on the ball to bring it to rest in 0.1 sec?

Answer:

Two beneficial aspects of the last 10,000 years of mankind have been the development of writing and the development of civilized communities.

Thus, writing has allowed the recording of the different historical events that have taken place during the development of humanity, setting precedents for subsequent generations, allowing documenting the progress that humanity has been achieving. On the other hand, the development of civilized communities around urban systems has allowed for greater economic and social development on the part of human groups, which through cooperation have been acquiring an increasingly higher quality of life.

On the other hand, two negative aspects of these years have been the world overpopulation and the pollution of the planet.

Thus, the amount of the world's population has been getting closer and closer to the limit of our planet's carrying capacity, which could lead humanity to a point where resources are definitely scarce, causing famines and various catastrophes. On the other hand, the pollution arising from the development of industrial societies has notably undermined the health of individuals and has damaged their standard of living, while causing irreparable damage to the natural environment.

Answer:

efficiency of a machine is less than 100% because some part is energy is utilized to overcome some opposing forces like friction which is wasted as heat ,sound energy etc

Explanation:

Answer:

protons+neutrons= mass number, so if the mass number is 13 and protons are 6 its 13-6=7 neutrons

Explanation:

mass number: the sum of the number of protons and

neutrons in an atom

this is key as it explains that protons+neutrons= mass number, so if the mass number is 13 and protons are 6 its 13-6=7 neutrons

Speed = distance / time

Speed = 120 km / 2 1/2 hours

Speed = 48 km per hour

This question is incomplete, the complete question is;

People who do very detailed work close up, such as jewelers, often can see objects clearly at much closer distance than the normal 25 cm.

a) What is the power in D of the eyes of a woman who can see an object clearly at a distance of only 8.50 cm? (Assume the lens-to-retina distance is 2.00 cm.)

b) What is the size in mm of an image of a 8.00 mm object, such as lettering inside a ring, held at this distance? (Include the sign of the value in your answer.)  __ mm

Answer:

1) the power in D of the eyes of a woman is 61.7647 D

2) the size in mm of an image of a 8.00 mm object is -1.882 mm

Explanation:

Given the data in the question;

a) power in D of the eyes of woman who can see an object clearly at a distance of only 8.5 cm and the lens-to-retina distance is 2.00 cm,

so

u = 8.5 cm = ( 8.5 / 100 )m = 0.085 m

v = 2.00 cm = ( 2 / 100 )m =  0.02 m

Now, we know that power of lens p = 1 / u + 1 / v

so we substitute

p = ( 1 / 0.085 ) + ( 1 / 0.02 )

p = 11.7647 + 50

p = 61.7647 D

Therefore,  the power in D of the eyes of a woman is 61.7647 D

b) What is the size in mm of an image of a 8.00 mm object, such as lettering inside a ring, held at this distance? (Include the sign of the value in your answer.)

we know that;

m = -v / u

we substitute

m = -0.02 / 0.085

m = -0.2353

since H₀ = 8.0 mm

H[tex]_i[/tex] = m × H₀

H[tex]_i[/tex] = -0.2353 × 8.0

H[tex]_i[/tex] = -1.882 mm

the size in mm of an image of a 8.00 mm object is -1.882 mm

Answer:

V = 33.12 V

Explanation:

Given that,

A 9.2 resistor and a 5.2 resistor are connected in series with a battery.

The potential difference across the 5.2 resistors is measured as 12 V.

In series combination of resistors, the current is same throughout the circuit. Let I is the current. Using Ohm's law,

[tex]I=\dfrac{V}{R}[/tex]

Put all the values,

[tex]I=\dfrac{12}{5.2}\\\\I=2.30\ A[/tex]

The equivalent resistance is :

R = 9.2 + 5.2

= 14.4 ohms

Let V os the potential difference across the battery. So,

[tex]V=2.3\times 14.4\\\\V=33.12\ V[/tex]

So, the potential difference across the battery is equal to 33.12 V.

White Dwarf Stage

Answer:yeah it A

Explanation:

Answer:

Option 2

Explanation:

The complete question is

A 50 kg child sits on the left side of the bathtub. A small toy boat of 0.5 kg is on the right side of the bathtub. Which part of the bathtub has the greatest pressure

Solution

It is the bottom of the bucket that will high pressure because of the additional weight of 50 Kg boy along with the weight of the water and the tub itself.

Pressure acts in the down ward direction and is equal to the force/weight divided by the area.

Hence, option 2 is correct

Answer:

the distance of image from the vertex is 45 cm and the image formed is in the glass.

Explanation:

distance of object, u = - infinity

radius of curvature, R = - 15 cm

refractive index, n = 1.5

Let the distance of image is v.

Use the formula

[tex]-\frac{n1}{u}+\frac{n2}{v}=\frac{n2- n1}{R}\\\\-\frac{1}{\infty }+\frac{1.5}{v}=\frac{1.5-1}{-15}\\\\v=45 cm[/tex]

The image is in the glass.  

The question is incomplete. The complete question is :

Iron β is a solid phase of iron still unknown to science. The only difference between it and ordinary iron is that Iron β forms a crystal with an fcc unit cell and a lattice constant, a = 0.352 nm. Calculate the density of Iron β.

Solution :

The density is given by :

[tex]$\rho = \frac{ZM}{a^3N_0} \ \ g/cm^3$[/tex]         ..................(i)

Here, Z = number of atoms in a unit cell

         M = atomic mass

         [tex]$N_0$[/tex] = Avogadro's number = [tex]$6.022 \times 10^{23}$[/tex]

          a = edge length or the lattice constant

Now for FCC lattice, the number of atoms in a unit cell is 4.

So, Z = 4

Atomic mass of iron, M = 55.84 g/ mole

Given a  = 0.352 nm = [tex]$3.52 \times 10^{-8}$[/tex] cm

From (i),

[tex]$\rho = \frac{ZM}{a^3N_0} $[/tex]      

[tex]$\rho = \frac{4 \times 55.84}{(3.52 \times 10^{-8})^3 \times 6.022 \times 10^{23}} $[/tex]

  [tex]$= 8.51 \ \ g \ cm ^{-3}$[/tex]

Therefore, the density of Iron β is [tex]$ 8.51 \ \ g \ cm ^{-3}$[/tex].

Answer:

heat

Explanation:

heat is the answer hdhhdhdhdhdhdhdhdhdhd

Answer:

Explanation:

For time period of revolution , the expression is as follows .

T² =  4π² R³ /GM , M is mass of the earth.

Putting the values

T² =  4π² (7880 x 10³)³ /(6.67 x 10⁻¹¹ )( 5.97 x 10²⁴ )

T² = 4.846 x 10⁷ s

T = 6.961 x 10³ s

= 6961 s

= 116 minutes .

Answer:

circuit breaker

Explanation:

A circuit breaker is a device used for electrical safety. It consists of a switch designed to protect an electrical circuit from damage that may result from heating due to overload in the circuit.

Its basic function is to interrupt current flow through its switch that consists of metal stripe which bends when it gets hot.

Fuse has similar action with circuit breaker, the only difference is that fuse can only be used once because it melts when it gets hot.

Therefore, the correct answer is "circuit breaker"

Answer:

Explanation:

From the missing image attached below, it is obvious that there no external force. This implies that they cannot change their position by merely just pulling the ropes. As a result, there will be no movement and no net force will exist.

So, if there is no external force;

The center of mass of the two people is:

[tex]X_{cm}= \dfrac{m_1x_1+m_2x_2}{m_1+m_2} \\ \\ X_{cm}= \dfrac{m(-3m)+m(+3m)} {m+m}\\ \\ X_{cm}= \dfrac{0}{2m} \\ \\ X_{cm} =0[/tex]

Thus, In the system, no movement occurs and all forces remain the same.

Answer:

In some situations, matter demonstrates wave behavior rather than particle behavior. This is best illustrated by which phenomenon is:

C. Interference patterns of electrons.

Answer:

C. Interference patterns of electrons

Answer:

t = 4.08 s

Explanation:

if the body is thrown upward, it has negative gravity. Knowing through the International System that the earth's gravity is 9.8 m/s²

Data:

Use formula:

Replace and solve:

Time taken by it to reach max height is 4.08 seconds.

Greetings.

Answer:

39.40 MeV

Explanation:

Determine the minimum possible Kinetic energy

width of region = 5 fm

From Heisenberg's uncertainty relation below

ΔxΔp ≥ h/2 , where : 2Δx = 5fm ,  Δpc = hc/2Δx = 39.4 MeV

when we apply this values using the relativistic energy-momentum relation

E^2 = ( mc^2)^2 + ( pc )^2 = 39.4 MeV ( right answer ) because the energy grows quadratically in nonrelativistic approximation,

Also in a nuclear confinement ( E, P >> mc )

while The large value will portray a Non-relativistic limit  as calculated below

K = h^2 / 2ma^2 = 1.52 GeV

Answer:

required distance is 233.35 m

Explanation:

Given the data in the question;

Sound intensity [tex]I[/tex] = 1.62 × 10⁻⁶ W/m²

distance r = 165 m

at what distance from the explosion is the sound intensity half this value?

we know that;

Sound intensity [tex]I[/tex] is proportional to 1/(distance)²

i.e

[tex]I[/tex] ∝ 1/r²

Now, let r² be the distance where sound intensity is half, i.e [tex]I[/tex]₂ = [tex]I[/tex]₁/2

Hence,

[tex]I[/tex]₂/[tex]I[/tex]₁ = r₁²/r₂²

1/2 = (165)²/ r₂²

r₂² = 2 × (165)²

r₂² = 2 × 27225

r₂² = 54450

r₂ = √54450

r₂ = 233.35 m

Therefore, required distance is 233.35 m

Answer:

Explanation:

It is a case of adiabatic expansion .

[tex]T_1V_1^{\gamma-1}=T_2V_2^{\gamma-1}[/tex]

T₁ , T₂ are initial and final temperature , V₁ and V₂ are initial and final volume.

Given ,

V₂ = 3 V₁ and T₁ = 292 . γ for air is 1.4 .

[tex]( 3 )^{\gamma-1}= \frac{292}{ T_2}[/tex]

[tex]( 3 )^{1.4-1}= \frac{292}{ T_2}[/tex]

1.552 = 292 / T₂

T₂ = 188 K .

Answer:

Explanation:

In a Solid sphere; the moment of inertia around its geometrical axis can be expressed by using the formula:

[tex]\mathtt{I_s = \dfrac{2}{5} M_s R^2_s}[/tex]

For the solid disk; the moment of inertia around the central axis is:

[tex]\mathtt{I_D= \dfrac{1}{2}M_DR_D^2}[/tex]

Suppose [tex]M_D = M_S[/tex]; then we can say both to be equal to M

As well as [tex]R_D = R_S[/tex]; then that too can be equal to R

Now;

[tex]\mathtt{I_s = \dfrac{2}{5} M R^2} --- (1)[/tex]

[tex]\mathtt{I_D= \dfrac{1}{2}MR^2}---(2)[/tex]

Multiplying equation (1) by 2, followed by dividing it by 2; we have:

[tex]\mathtt{I_s= \dfrac{2}{5}MR^2} \times \dfrac{2}{2}[/tex]

[tex]I_s = \dfrac{4}{5} \times \dfrac{1}{2}MR^2 \\ \\ I_s = \dfrac{4}{5}\times I_D \\ \\ I_s > I_D[/tex]

Answer:

a)   p = 4.167 cm, b)   m = + 6

Explanation:

a) For this exercise we must use the equation of the constructor

          [tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}[/tex]

where f is the focal length, p and q are the distance to the object and the image, respectively

In this case the distance to the image q = 25 cm and the focal length is f = 5.0 cm

Since the object and its image are on the same side of the lens, the distance to the image by the sign convention must be negative.

       [tex]\frac{1}{p } = \frac{1}{f} - \frac{1}{q}[/tex]

      [tex]\frac{1}{p} = \frac{1}{5} - \frac{1}{-25}[/tex]

      [tex]\frac{1}{ p}[/tex] = 024

      p = 4.167 cm

b) angular magnification

     m = h ’/ h = - q / p

     m = - (-25) /4.167

     m = + 6

the positive sign indicates that the image is straight and enlarged

Answer: See explanation

Explanation:

The evolutionary stages for the formation of planets from earliest to latest will be:

1. Dust keeps matter inside the disk cool enough for planet formation to start

2. Dust grains form condensation nuclei on which surrounding atoms condense to form small clumps of matter.

3. Small clumps of matter stick together via the process of accretion to form planetesimals a few hundred kilometers in diameter.

4. Planetesimals begin to accrete, forming protoplanets.

5. A collection of a few planet-sized protoplanets remain in a fairly cleared out disk around the star

Answer:

1.32kgm/s

Explanation:

use the formula: p=mv

The momentum of a lab cart  = -1.32 kg m/s

It is measure of the inertia of a body/ object .It can be calculated by multiplying mass with velocity .

General formula for momentum = M = m * v

given

mass = 0.60  kg

speed = 2.2 m/s

velocity = - 2.2 m/s ( answer is in negative , since mass is a scaler quantity  but velocity is a vector quantity  hence ,  velocity can be negative )

momentum = mass * velocity

                   = 0.60 * (-2.2 ) = -1.32 kg m/s

The momentum of a lab cart  =c) -1.32 kg m/s

learn more about momentum

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Answer:

a)I=V/R

39.5 amp

Explanation:

because the voltage in serious with 1ohm resistor

Answer:

A) F = V²E_o•πr²/2d²

B) U = E_o•Aπr²V²/2d

Explanation:

A) Since we have two circular plates, the formula for the electric field is expressed as;

E = V/d

Where;

V is voltage

d is distance

However, the net electric field produced is given by;

E' = V/2d

The tension in the cable can then be expressed as;

F = qE'

Where q is charge

Thus;

F = qV/2d - - - (eq 1)

We also know that;

C = q/V = E_o•A/d

A is area = πr²

Thus;

q/V = E_o•πr²/d

q = VE_o•πr²/d

Let's put VE_o•πr²/d for q in eq 1 to get;

F = V²E_o•πr²/2d²

B) formula for the energy stored in the electric field is;

U = ½CV²

From earlier, we saw that; C = E_o•A/d

Thus;

U = ½E_o•AV²/d

A = πr²

Thus;

U = E_o•Aπr²V²/2d

Given :

A 0.50-kg mass is attached to a spring of spring constant 20 N/m along a horizontal, frictionless surface.

The object oscillates in simple harmonic motion and has a speed of 1.5 m/s at the equilibrium position.

To Find :

At what location are the kinetic energy and the potential energy the same.

Solution :

Let, at location x from the equilibrium position the kinetic energy and the potential energy the same.

So,

[tex]P.E = K.E\\\\\dfrac{kx^2}{2} = \dfrac{mv^2}{2}\\\\x = v\sqrt{\dfrac{m}{k}}\\\\x = 1.5 \times \sqrt{\dfrac{0.5}{20}}\ m\\\\x = 0.238 \ m[/tex]

Hence, this is the required solution.

Answer:

The speed will be "0.144 rad/s".

Explanation:

Given that,

Diameter,

d = 7.50 km

Radius,

R = [tex]\frac{7.5}{2} \ Km[/tex]

Acceleration on inner curve,

= 8 times

Now,

As we know,

⇒ [tex]\omega^2R=8g[/tex]

or,

⇒ [tex]\omega=\sqrt{\frac{8g}{R} }[/tex]

On substituting the values, we get

⇒     [tex]=\sqrt{\frac{8\times 9.8}{\frac{7.5}{2}\times 10^3 } }[/tex]

⇒     [tex]=\sqrt{\frac{78.4}{3750} }[/tex]

⇒     [tex]=\sqrt{0.0209}[/tex]

⇒     [tex]=0.144 \ rad/s[/tex]