An unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 43.0 km . To the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s .If nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?

Answers

Answer 1

Answer: v₂ = 5962 km

the spacecraft  will crash into the lunar surface at a speed of 5962 km if nothing is done to correct its orbits

Explanation:

Given that;

Lunar surface is in an altitude h = 43.0 km =  43 × 10³ m

we know; Radius of moon R₁ = 1.74 × 10⁶, mass of moon = 7.35 × 10²²

speed of the space craft when it crashes into the lunar surface , v

decreasing speed of the space craft = 23 m/s

Now since the space craft travels in a circular orbit, we use centrifugal expression Fe = mv²/r

but the forces is due to gravitational forces between space craft and lunar surface Fg = GMn/r²

HERE r = Rm + h

we substitute

r = 1.74 × 10⁶ m + 43 × 10³ m

= 1.783 × 10⁶ m

On equating these, we have

G is gravitational force ( 6.673 × 10⁻¹¹ Nm²/kg²)

v²/r = GM/r²

v = √ ( GM/r)

v = √ ( 6.673 × 10⁻¹¹ Nm²/kg² × 7.35 × 10²² / 1.783 × 10⁶ )

v = √ (2750787.9978)

v = 1658.55 m/s

Now since speed is decreasing by 23 m/s

the speed of the space craft into the lunar face is,

v₁ = 1658.55 m/s - 23 m/s

v₁ = 1635.55 m/s

Now applying conversation of energy, we say

1/2mv₂² = 1/2mv₁² + GMem (1/Rm - 1/r)

v₂ =  √ [ v₁² + GMe (1/Rm - 1/r)]

v₂ =   √ [ 1635.55²  + ( 6.673 × 10⁻¹¹ Nm²/kg² × 7.35 × 10²²) (1/ 1.74 × 10⁶ - 1 / 1.783 × 10⁶)]

v₂ =  √ (2675023.8025 + 67979.24)

v₂ = √(2743003.046)

v₂ = 1656.2 m/s

now convert

v₂ = 1656.2 × 1km/1000m × 3600s/1hrs

v₂ = 5962 km

Therefore the spacecraft  will crash into the lunar surface at a speed of 5962 km if nothing is done to correct its orbits


Related Questions

What is the magnitude of the momentum of a 33 g sparrow flying with a speed of 8.7 m/s?

Answers

Answer:

0.2871 kg m/s

Explanation:

p = mv

convert 33g into kg (0.033)

mulitply byt 8.7 to get 0.2871

Ball A is dropped from the top of a building. At the same instant ball B is thrown vertically upwards from the ground. When the balls collide, they are moving in opposite direction and the speed of A is twice the speed of B. At what fraction of the height of the building did the collision occurs ?

Answers

Answer:

  y/y₀ = 1/2 + v₀²/(2 g y₀)

Explanation:

         This in a kinematics exercise in a mention  

ball A.  

Since the ball is dropped, its velocity starts at zero, at the meeting point the equation is  

[tex]v_{A}^2[/tex]= - 2 g (y₀-y)  

ball B  

v_{B}^2 = v₀² - 2 g y

we substitute  

               2v_{B}^2 = -2 g (y₀ -y)  

               v_{B}^2 = - g y₀ + 2g y  

              v_{B}^2 = v₀² - 2gy

we have a system of two equations with two unknowns, therefore it can be solved. Let's multiply-by -1 and add  

       0 = g y₀ + v₀² -2gy  

we clear the height  

      y = (g yo + v₀²) / 2g  

     y = yo / 2 + v₀² / 2g

In this exercise we assume that the height of the building is known and the initial velocity of ball B  

The fraction is

y/yo = 1/2 + v₀²/(2gyo)

The path of an object projected at a 45 degree angle with initial velocity of 80 feet per second is given by the −32 2 function h(x) = (80)2 x + x where x is the horizontal distance traveled and h(x) is the height in feet. Use the TRACE feature of your calculator to determine the height of the object when it has traveled 100 feet away horizontally.

Answers

Answer:

The height of the object is 50 feet

Explanation:

Given that:

The path of an object projected at a 45 degree angle with initial velocity of 80 feet per second is given by the  function  [tex]h (x) =\dfrac{-32}{(80)^2}x^2+x[/tex]

where;

x  is the horizontal distance traveled and  h(x) is the height in feet.

The objective is to use the TRACE feature of your calculator to determine the height of the object when it has traveled 100 feet away horizontally.

Before then;

If the function [tex]h (x) =\dfrac{-32}{(80)^2}x^2+x[/tex]

and x = 100

then :

[tex]h (x) =\dfrac{-32}{(80)^2}(100)^2+100[/tex]

[tex]h (x) =\dfrac{-32}{6400} \times 10000+100[/tex]

[tex]h (x) =- 0.005 \times 10000+100[/tex]

[tex]h (x) =- 50+100[/tex]

h(x) = 50 feet

Using the TRACE CALCULATOR,

In your Trace calculator;

input Y = X - 32 X^2/(80)        this  because in the calculator Y denotes h(x)

Now over to the WINDOW

set the window as follows:

Xmin = 0

Xmax = 200

Xsc1 =1

Ymin = 0

Ymax = 50

Ysc = 1

Xres = 1

After that, click on the graph key and an output will display as seen in the image below.

Therefore, the show the value of Y which we earlier said it denotes the h(x) = 50 feet

A 121-kg astronaut (including space suit) acquires a speed of 2.90 m/s by pushing off with her legs from a 1600-kg space capsule. Use the reference frame in which the capsule is at rest before the push.
A) What is the velocity of the space capsule after the push in the reference frame?
B) If the push lasts 0.660 s , what is the magnitude of the average force exerted by each on the other?
C) What is the kinetic energy of the astronaut after the push in the reference frame?
D) What is the kinetic energy of the capsule after the push in the reference frame?

Answers

Answer:

a) 0.22 m/s

b) 531.67 N

c) 508.81 J

d) 38.72 J

Explanation:

the mass of the astronaut = 121 kg

astronaut's push of speed = 2.9 m/s

mass of the space capsule = 1600 kg

a) according to the conservation of momentum, the summation of the total momentum in a system must be equal to zero.

let us take the direction of the astronaut as positive.

Astronaut's momentum p = mv

where

m is the mass

v is the velocity

momentum p = 121 x 2.9 = 350.9 kg-m/s

The space capsules momentum = mv

==> 1600 x (-v) = -1600v    this is because the space capsule moves in the opposite direction to the astronaut.

according to conservation of momentum

350.9 + (-1600v) = 0

350.9 = 1600v

v = 350.9/1600 = 0.22 m/s

b) magnitude of the force F is the rate of change of momentum.

The astronaut and the space capsule both change momentum from 0 to 350.9 kg-m/s. In 0.66 seconds, the force will be

F = [tex]\frac{m(v - u)}{t}[/tex]

where

u is their initial velocity = 0 m/s

where v = 2.9

t = 0.66

substituting, we have

F = [tex]\frac{121(2.9 - 0)}{0.66}[/tex] = 350.9/0.66 = 531.67 N  this same force is experienced by the space capsule

c) Kinetic energy of the astronaut = [tex]\frac{1}{2} mv^{2}[/tex]

m is the mass = 121 kg

v is the velocity = 2.9 m/s

KE = [tex]\frac{1}{2}*121*2.9^{2}[/tex] = 508.81 J

d) Kinetic energy of the space capsule = [tex]\frac{1}{2} mv^{2}[/tex]

KE = [tex]\frac{1}{2}* 1600* 0.22^{2}[/tex] = 38.72 J

A cylinder contains 3.5 L of oxygen at 350 K and 2.7 atm . The gas is heated, causing a piston in the cylinder to move outward. The heating causes the temperature to rise to 620 K and the volume of the cylinder to increase to 9.1 L.What is the gas pressure? P= _____atm

Answers

Answer:

The pressure is [tex]P_2 = 1.84 \ a.t.m[/tex]

Explanation:

From the question we are told that

   The first  volume of  is  [tex]v_1 = 3.5 \ L[/tex]

   The first  pressure is  [tex]P_1 = 2.7 \ a.t.m[/tex]

   The first  temperature is  [tex]T_1 = 350 \ K[/tex]

    The  new temperature is  [tex]T_2 = 620 \ K[/tex]

     The  new volume is  [tex]V_2 = 9.1 \ a.t.m[/tex]

Generally according to the combined gas law we have that

      [tex]\frac{P_1 V_1 }{T_1 } = \frac{P_2 V_2 }{T_2 }[/tex]

=>  [tex]P_2 = \frac{P_1 * V_1 * T_2 }{T_1 * V_2 }[/tex]

=>    [tex]P_2 = \frac{ 2.7 * 3.5 * 620 }{ 350 * 9.1 }[/tex]

=>  [tex]P_2 = 1.84 \ a.t.m[/tex]

A horizontal rope is tied to a 55.0 kg box on frictionless ice. What is the tension in the rope if: The box is at rest

Answers

Answer:

T = 0

Explanation:

Given that,

Mass of the box, m = 55 kg

We need to find the tension in the rope if the box is at rest. When the object is at rest, its acceleration is equal to 0. It would mean that the net force equals 0. So, the tension in the rope is equal to 0.

What is the power in a circuit that has a current of 12 amps and a resistance of 100 ohms? a. 14,400 watts b. 8.3 watts c. 144 watts d. 1200 watts

Answers

Answer:

a. 14,400 Watts

Explanation:

Power is current times voltage.

P = IV

Voltage is current times resistance.

V = IR

Substitute:

P = I²R

P = (12 A)² (100 Ω)

P = 14,400 W

A toy of mass 0.190-kg is undergoing SHM on the end of a horizontal spring with force constant k = 350 N/m . When the toy is a distance 0.0140 m from its equilibrium position, it is observed to have a speed of 0.400 m/s .
A) What is the toy's total energy at any point of its motion?
B) What is the toy's amplitude of the motion?
C) What is the toy's maximum speed during its motion?

Answers

Answer

a)0.0495 J

b)0.01681 m

c)0.7218 m/s

Explanation:

Given

Mass of the.toy M = 0.190 kg

force constant k = 350 N/m

Displacement from equilibrium x = 0.0140 m

Speed v = 0.400 m/s

a)What is the toy's total energy at any point of its motion?

The total energy at any point of it's motion can be calculated by adding together both the potential and kinetic energy of the toy, since it's posses potential energy when at rest and kinetic energy at motion

Total energy E = kinetic energy + potential energy

E = ¹/₂mv² + ¹/₂kx²

E = ¹/₂ (0.190)(0.4)² + ¹/₂ (350)(0.0140)²

E = 0.0495 J

Hence,the total energy is 0.0495 J

b) the amplitude of the motion can be calculated using below formula

Let amplitude = A

E = ¹/₂KA²

if we make Amplitude A the subject of the formula we have

A=√(2E/k)

But we have calculated our E up there, our K was given in question then if we substitute we have

A= √(2×0.0495)/350

Ans: 0.01681 m

Hence, our Amplitude is 0.01681 m

c) the the toy's maximum speed during its motion can be calculated using the expression below

Let maximum speed = vmax

E = (1/2)M * vmax^2

If we make vmax the subject of the formula we have

vmax =√(2E/m)

vmax= √(2×0.0495)/0.190

vmax=0.7218 m/s

Hence our vmax is 0.7218 m/s

In a photoelectric experiment, a metal is irradiated with light of energy 3.56 eV. If a stopping potential of 1.10 V is required, what is the work function of the metal?

Answers

Answer:

The  work function is  [tex]\phi = 2.46 \ eV[/tex]

Explanation:

From the question we are told that

    The light energy is  [tex]E = 3.56 eV[/tex]

     The  stopping voltage is  [tex]V = 1.10 \ V[/tex]

Generally work function is mathematically represented as

      [tex]\phi = E - KE[/tex]

Where KE is the kinetic energy of the ejected electron and it is mathematically represented as

         [tex]KE = V * e[/tex]

Where  e is the charge on the electron

So  

        [tex]KE = 1.10eV[/tex]

Thus  

        [tex]\phi = 3.56eV - 1.10 eV[/tex]

=>      [tex]\phi = 2.46 \ eV[/tex]

A diffraction-limited lens can focus light to a 10-μ m-diameter spot on a screen. Do the following actions make the spot diameter larger, smaller, or leave it unchanged? a. Decreasing the wavelength of light: b. Decreasing the lens diameter c. Decreasing the focal length: d. Decreasing the lens-to-screen distance:

Answers

Answer:

a) the size of the sport DECREASES  , b)the spot size is increased

c)  it has no effect  and d) spot size DECREASES

Explanation:

The expression for constructive interference in diffraction is

         a sin θ = m λ

the chaff of the spot is given by the minimum interference m = 1

           a sin θ = λ

let's use trigonometry to find the angle

         tan λ= y / L

         tan θ = sin θ / cos t = sin θ

         sin θ = y / L

          a y / L = lam

in the case of materials with circular dome, the problem must result in polar coordinates, with which a numerical constant is introduced

          y = 1.22 L / a lam

let's analyze each electrode action in this equation

a) Decrease lam

         y ’= 1.22 L / a lm2

          lam2 <lamo

          y '<y

therefore the size of the sport DECREASES

b) decreases the lens diameter

       a '<a

         y ’= 1.22 L / a’ lam

         y '> y

the spot size is increased

c) Decrease the focal length

The expression does not depend on the focal length, so it has no effect

d) decrease in L

         y ’= 1.22 L’ / a lam

spot size DECREASES

A positron and an electron annihilate each other upon colliding, thereby producing energy in the form of two gamma rays. Assuming that both gamma rays have the same energy (since both particles have the same mass), calculate the wavelength of the electromagnetic radiation used in pm. (1 pm = 10⁻¹² m; mass of electron (amu) = 0.000549)

Answers

Answer:

2.42631E-13m

Explanation:

First we find the mass defect

Which is m= 0-2(9.10939E-33kg)

= - 1.82188E-30kg

Now find the energy

S

E= mc²=( -18.82188E-30)(2.999792E8)²

= 1.63742E-13J

Thus energy per photon will be

1.63742E-13J/2= 8.18710E-14J

So wavelength is given as

Lambda= hc/E

= (6.62608E-34)(2.997E8)/8.18710J

= 2.42631E-13m

The wavelength of radiation used to annihilate a positron and an electron is required.

The wavelength of the electromagnetic radiation used is 2.42 pm.

The mass of positron and electron are equal

m = Mass = [tex]\dfrac{0.000549}{6.022\times 10^{26}}=9.11\times 10^{-31}\ \text{kg}[/tex]

c = Speed of light = [tex]3\times 10^{8}\ \text{m/s}[/tex]

h = Planck's constant = [tex]6.626\times 10^{-34}\ \text{Js}[/tex]

Total energy in the collision is

[tex]E_T=mc^2+mc_2\\\Rightarrow E_T=2mc^2\\\Rightarrow E_T=2\times 9.11\times 10^{-31}\times (3\times 10^{8})^2\ \text{J}[/tex]

Energy released per photon is

[tex]E=\dfrac{E_T}{2}\\\Rightarrow E=\dfrac{2\times 9.11\times 10^{-31}\times (3\times 10^{8})^2}{2}\\\Rightarrow E=9.11\times 10^{-31}\times (3\times 10^{8})^2\ \text{J}[/tex]

Energy is given by

[tex]E=\dfrac{hc}{\lambda}\\\Rightarrow \lambda=\dfrac{hc}{E}\\\Rightarrow \lambda=\dfrac{6.626\times 10^{-34}\times 3\times 10^8}{9.11\times 10^{-31}\times (3\times 10^{8})^2}\\\Rightarrow \lambda=2.42\times 10^{-12}\ \text{m}=2.42\ \text{pm}[/tex]

The wavelength of the electromagnetic radiation used is 2.42 pm.

Learn more:

https://brainly.com/question/13187526?referrer=searchResults

How does the energy stored in an isolated capacitor change if the potential difference is increased by a factor of six

Answers

Answer:

Energy will be reduced by 0.3

Explanation:

Given that E = 1/2 QV

So if V is increased by 6

=> V = E/ 3Q

So the energy will be divided by a factor 1/3 of be reduced by 0.3

When asked how to create an electromagnet, the best answer would be:

"You can create an electromagnet by applying a direct current to a non–magnetic material in order to create an electromagnetic field."
"You can create an electromagnet by covering a wire with insulation and applying a direct electrical current to the magnet."
"You can create an electromagnet by coiling a ferromagnetic material, wrapping in an insulator, and applying a current to the coil."
"You can create an electromagnet by wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current."

Answers

Answer:

"You can create an electromagnet by wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current."

Explanation:

An electromagnet is created by coiling a ferromagnetic material with the help of an insulated wire around it and applying a  current . Insulated wire carrying current produces magnetic field around it . This field produces magnetic flux in the magnetic material and makes it magnet . When we switch of current , magnetic field ceases to exist and therefore , magnetic material ceases to be a magnet .

 

Explanation:

A student attaches a length of nylon fishing line to a fence post. She stretches it out and shakes the end of the rope in her hand back and forth to produce waves on the line. The most efficient way for her to increase the wavelength is to

Answers

Answer:

increase the tension on the hose and shake the end fewer times per second.

Explanation:

This is because Tension of the rope is directly proportional to wavelength and inversely proportional to the frequency ( shakes per second) so increasing tension increases wavelength and vice versa

Wavelength= Tension/ frequency

The most efficient way for her to increase the wavelength is to increase the rate of shaking the rope per second.

What is wavelength?

Wavelength measures the distance of wave that occur between one crest and another crest.

To increase the wavelength the rope end should be shaked in a number of time per second this will help build up tension in the rope.

Therefore, she should increase the rate of shaking the rope per second.

Learn more on wavelength here,

https://brainly.com/question/10750459

When submerged in water, the brick appears to have an additional force pushing it ___upward ___downward. This additional force is the buoyant force (B).

Answers

Answer:

Therefore, the brick appears to have an additional force pushing it upward.

Explanation:

When a brick is submerged in the water, it has two forces acting upon it. One force is the gravitational force or the weight of the brick, that acts downward. The weight force also acts on the brick when it is not in water. But, in water an additional force acts on the brick. This additional force is named as Buoyant Force. This force is equal to the weight of the water displaced by the brick. And this Buoyant Force acts on the brick in the upward direction. The formula for this force is given as follows:

Buoyant Force = (Density of Water)(Volume of Water Displaced)(g)

Therefore, the brick appears to have an additional force pushing it upward.

3.60×10^23 nitrogen molecules collide with a 16.0 cm^2 wall each second. Assume that the molecules all travel with a speed of 450 m/s and strike the wall head on. What is the pressure on the wall?

Answers

Answer:

The pressure on the wall is 9416.25 N/m²

Explanation:

Please see the attachments below

Cassidy walks 1 mile then turns 90 degrees and walks 2 miles Distance:Displacement:

Answers

Explanation:

The total displacement is 3 miles

What is displacement?

Simply put it is the sum total of the changes in position of an object from it initial position to it final position, It is a vector quantity and has a direction and magnitude.

In our example the displacement the total points of movement can be annotated as

From A to B to C

From A to B= 1 mile

From B to C= 1 miles

Displacement is 1 + 2= 3 miles

An organ pipe open at both ends has two successive harmonics with frequencies of 220 Hz and 240 Hz. What is the length of the pipe? The speed of sound is 343 m/s in air.

Answers

Answer:

The  value is  [tex]l = 8.58 \ m[/tex]

Explanation:

From the question we are told that

  The  frequencies of two successive harmonics  is  [tex]f_ a = 220 \ Hz[/tex] , [tex]f_b = 240 \ Hz[/tex]

   The  speed of sound in the air is  [tex]v = 343 \ m/s[/tex]

Generally a harmonic frequency is mathematically represented as

        [tex]f_n = \frac{n * v }{2l}[/tex]

here l is the length of the pipe

n is the order of position of the harmonics

 Now since we do not know the order of the given harmonic frequencies but we are told that they are successive then the frequencies can be mathematically represented as

     [tex]220 = \frac{n * v}{ 2 l }[/tex]

and

     [tex]240 = \frac{ (n+1 ) v }{2l}[/tex]

So  

    [tex]240 - 220 = \frac{ (n+1 ) v }{2l} - \frac{n * v}{ 2 l }[/tex]

   [tex]20 = \frac{v}{2l}[/tex]

=>   [tex]l = 8.58 \ m[/tex]

A medicine ball has a mass of 6 kg and is thrown with a speed of 4 m/s. What is its kinetic energy?
(24 j ) (48 J )(96 j )( 12j )
none of these​

Answers

Answer:

[tex] \boxed{\sf Kinetic \ energy \ (KE) = 48 \ J} [/tex]

Given:

Mass (m) = 6 kg

Speed (v) = 4 m/s

To Find:

Kinetic energy (KE)

Explanation:

Formula:

[tex] \boxed{ \bold{\sf KE = \frac{1}{2} m {v}^{2} }}[/tex]

Substituting values of m & v in the equation:

[tex] \sf \implies KE = \frac{1}{2} \times 6 \times {4}^{2} [/tex]

[tex] \sf \implies KE = \frac{1}{ \cancel{2}} \times \cancel{2} \times 3 \times 16[/tex]

[tex] \sf \implies KE =3 \times 16[/tex]

[tex] \sf \implies KE = 48 \: J[/tex]

In a double slit experiment, the intensity of light at the center of the central bright fringe is measured to be 6.2 µW/m2. What is the intensity half

Answers

Answer:

   I_FWHW = 3.2 μW / m²

Explanation:

In the analysis of optics and electricity a very useful magnitude is the width at half height (FWHW) and the intensity at this height, which is given by

               I_FWHW = I₀ / 2

corresponds to the width of the line for this intensity.

In this case they give the maximum intensity for which

               I_FWHW = 6.2 / 2

               I_FWHW = 3.2 μW / m²

You do not give more data in your exercise, but the most interesting calculation is to find the angle values ​​for which you have this intensity since it is this range is 50% of the energy of the system, have I write the equation for this calculation

             I = Io cos² x₁   (sin x / x)²

             x₁ = π d sin θ /λ

             x = π b sin θ /λ

where d is the separation of the slits and b the width of each slit

Silver has a work function of 4.5 eV . Part A What is the longest wavelength of light that will release an electron from a silver surface

Answers

Answer:

λ = 2.7608 x 10⁻⁷ m = 276.08 nm

Explanation:

The work function of a metallic surface is the minimum amount of photon energy required to release the photo-electrons from the surface of metal. The work function is given by the following formula:

Work Function = hc/λ

where,

Work Function = (4.5 eV)(1.6 x 10⁻¹⁹ J/1 eV) = 7.2 x 10⁻¹⁹ J

h = Plank's Constant = 6.626 x 10⁻³⁴ J.s

c = speed of light = 3 x 10⁸ m/s

λ = longest wavelength capable of releasing electron.

Therefore,

7.2 x 10⁻¹⁹ J = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/λ

λ = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(7.2 x 10⁻¹⁹ J)

λ = 2.7608 x 10⁻⁷ m = 276.08 nm

According to the chart, one gram of copper and
gram(s) of gold
would change their temperatures by approximately the same amount by
adding heat to them.
A) one
B) two
C) three
D) four

Answers

Answer:

C) three

Explanation:

Let gram of gold required be m . Let temperature change in both be Δ t .

heat absorbed = mass x specific heat x change in temperature

for copper

heat absorbed = 1 x .385 x Δt

for gold

heat absorbed = m x .129 x Δt

So

m x .129 x Δt = 1 x .385 x Δt

m = 2.98

= 3 g approximately .

A train is travelling along a straight track at constant velocity from Western Station to Eastern station. The mile markers increase towards the east. A passenger notices that, at mile marker 25, the reading on this stopwatch is 15 minutes, and at mile marker 60, the reading on this stopwatch is 45 minutes. What is the velocity of the train in meters per second

Answers

Answer:

Explanation:

Displacement of train = 60 - 25 = 35 mile

= 35 x 1.6 = 56 km

duration of time = 45 - 15 = 30 minutes

= 30 x 60 = 1800 s

velocity of train = displacement / time

= 56 / 1800 = .03111 km /s

= 31.111 m / s

Select the correct answer.
Based on the law of conservation of energy, which statement is false?
O A. Energy is lost when machines don't work right.
OB.
We can't add more energy to the universe.
Ос.
We can't destroy energy that exists in the universe.
OD. Energy changes from one form to another.​

Answers

Answer:A is the correct answer

Explanation:

Friction: During a hockey game, a puck is given an initial speed of 10 m/s. It slides 50 m on the horizontal ice before it stops due to friction. What is the coefficient of kinetic friction between the puck and the ice

Answers

Answer:

The  value is  [tex]\mu_k = 0.102 0[/tex]

Explanation:

From the question we are told that

    The initial speed is  [tex]u = 10 \ m/s[/tex]

    The  distance traveled is  [tex]d = 50 \ m[/tex]

 

Generally we can obtain the acceleration using the kinetic equation as follows

     [tex]v^2 = u^2 + 2as[/tex]

=>   [tex]a = \frac{v^2 - u^2 }{ 2s}[/tex]

=>   [tex]a = \frac{0^2 - 10^2 }{ 2 * 50 }[/tex]

=>   [tex]a = -1 m/s^2[/tex]

The  negative sign shows that the pluck is decelerating

  The force driving the pluck is mathematically evaluated as

       [tex]F = ma[/tex]

 This force is also equivalent to the frictional force acting on the pluck

So  

      [tex]ma = m * g* \mu_k[/tex]

=>  [tex]\mu_k = \frac{a}{g}[/tex]

=>   [tex]\mu_k = \frac{1}{9.8 }[/tex]

=>   [tex]\mu_k = 0.102 0[/tex]

A gas is compressed by an isothermal process that decreases its volume by a factor of 2. In this process, the pressure:________

a. Does not change
b. Increases by a factor of less than 2.
c. Increases by a factor of 2.
d. Increases by a factor of more than 2.

Answers

Answer:

In this process, the pressure increases by a factor of 2.

Explanation:

For an isothermal process, the temperature remains constant throughout the process.

Also, PV = constant

It means that there is an inverse relationship between pressure and volume of the gas.

If the volume is decreased by a factor of 2, the pressure increases by a factor of 2. Hence, the correct option is (c).

A toy car travels at 5.3 m/s. The car travels a distance of 17.8 m. How long did it
take to travel that distance?

Answers

Explanation:

Assuming constant speed:

Distance = speed × time

17.8 m = (5.3 m/s) t

t = 3.36 s

which of the following graphs shows the motion of an object that starts to travel forward, stops for several seconds, and then returns to its original position

Answers

Answer:

B

Explanation:

in graph B, you can see that the position increases and remains constant for a while before returning to 0

Which of the following is not a factor in whether a reaction will spontaneously occur? A. Entropy change of the system B. Enthalpy change of the system C. Temperature of the system D. Pressure change of the system

Answers

Answer:

D

Explanation:

pressure change have nothing to do with the spontaneity.

Entropy change , enthalpy change , temperature have roles in deciding spontaneity.

What is the main reason why would a fan be expected to warm the air that passes through it? A or B?
A. The fan does work on the air in the room leading to an increase in its thermal energy and temperature.
B.The fan transfers heat to the air in the room leading to an increase in its thermal energy and temperature.

Answers

Answer:

A. The fan does work on the air in the room leading to an increase in its thermal energy and temperature.

Explanation:

Fans move fluid, typically a gas, such as air, through a room or an enclosure. A fan consists of a rotating arrangement of vanes or blades (impeller), which acts on the air. The action of the impeller does work on the fan by compressing and moving the air forward, doing work on it in the process. The work done on the fan leads to an increase in the thermal energy of the air.

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