A child sleds down a snowy hillside starting from rest. The hill has a 15 degree slope, with a long stretch of level field at the foot. The child starts 50 ft up the slope and continues for 100 ft on the level field before coming to a complete stop. Find the coefficient of friction between the sled and the snow, assuming that it is constant throughout the ride. Neglect air resistance.

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Given :

On the way home from school, Mr. X drives the first 10 miles at 55 mi/hr, the next 20 miles at 70 mi/hr, and the last 5 miles at 35 mi/hr.

To Find :

How far does Mr. X live from school.

Solution :

To find the distance between Mr. X residence from school is simply given by summing all the distance he travelled .

So, distance = 10 + 20 + 5 miles

distance = 35 miles.

Hence, this is the required solution.

Answer:

[tex]\phi=628.3[/tex]

Explanation:

From the question we are told that

Radius [tex]r=10.0 cm[/tex]

Magnetic field[tex]B=2T[/tex]

Generally the equation for area of circular path is mathematically given by

 [tex]Area=\pi r^2[/tex]

 [tex]A=\pi 10^2[/tex]

 [tex]A=314.15m^2[/tex]

Generally the equation for Magnetic flux is mathematically given by

 [tex]\phi=BA[/tex]

 [tex]\phi=2*314.15[/tex]

 [tex]\phi=628.3[/tex]

a) v = 1.94 × 10^5 m/s

b) Ms = 2.09 × 10^24 kg

Explanation:

Given:

m = 0.257M (M = mass of earth = 5.972×10^24 kg)

= 1.535×10^24 kg

r = 7.18×10^9 m

T = 2.7 days × (24 hr/1 day) × (3600 s/1 hr)

= 2.3328×10^5 s

a) To find the orbital speed of the planet, we need to find the circumference of the planet's orbit first:

C = 2×(pi)×r

= 2(3.14)(7.18×10^9m)

= 4.51×10^10 m

The orbital speed v is then given by

v = C/T

= (4.51×10^10 m)/(2.33×10^5 s)

= 1.94 × 10^5 m/s

b) We know that centripetal force Fc is given by

Fc = mv^2/r

where v = orbital speed

r = average orbital radius

m = mass of planet

We also know that the gravitational force FG between the star K2-116 and the planet is given by

FG = GmMs/r^2

where m = mass of planet

Ms = mass of star K2-116

r. = average orbital radius

G = universal gravitational constant

= 6.67 × 10^-11 m^3/kg-s^2

Equating Fc and FG together, we get

Fc = FG

mv^2/r = GmMs/r^2

Note that m and one of the r's get cancelled out so we are left with

v^2 = GMs/r

Solving for the mass of the star Ms, we get

Ms = rv^2/G

=(7.18 × 10^9 m)(1.94 × 10^5 m/s)^2/(6.67 × 10^-11 m^3/kg-^2)

= 2.09 × 10^24 kg

What is the primary evidence used to determine how the Moon formed?

[tex]\huge\color{purple}\boxed{\colorbox{black}{♡Answer}}[/tex]

A. Moon craters and Earth craters were caused by the same asteroid strike. ✅

[tex]\large\mathfrak{{\pmb{\underline{\orange{Happy\:learning }}{\orange{!}}}}}[/tex]

Answer:

Note the word "circular".

Meaning the area would be found using that of a circle = πr²

Recall

Pressure = Force/Area

Area = π x 0.5² = 0.785m²

Pressure = 20/0.785

= 25pa ( to the nearest whole number)

Pressure = Force/Area

As the table is circular, we have to use the formula of area of circle;

= πr²

= 3.14 × 0.5 × 0.5

= 3.14 × 0.25

= 0.785 m²

Put the values of force and area in formula;

= 20/0.785

= 20000/785

= 25.45 Pa

= 25 Pa (Approx)

Answer:

"8 units" is the appropriate answer.

Explanation:

According to the question,

Throughout equilibrium all particles are of equivalent intensity, and as such the integrated platform's total energy has been uniformly divided across all individuals.

Now,

The total energy will be:

= [tex]480+720[/tex]

= [tex]1200 \ units[/tex]

The total number of particles will be:

= [tex]50+100[/tex]

= [tex]150[/tex]

hence,

Energy of each A particle or each B particle will be:

= [tex]\frac{1200}{150}[/tex]

= [tex]8 \ units[/tex]

Answer:

3 pls give me brainliest

Explanation:

Answer:

θ = 33°

Explanation:

Here, we can use the formula for the total time of flight of a projectile to calculate the launch angle of frog:

[tex]T = \frac{2\ u\ Sin\theta}{g} \\\\Sin\theta = \frac{Tg}{2u}[/tex]

where,

θ = launch angle = ?

T = Total time of flight = 0.6 s

g = acceleration due to gravity = 9.81 m/s²

u = launch speed = 5.4 m/s

Therefore,

[tex]Sin\theta = \frac{(0.6\ s)(9.81\ m/s^2)}{(2)(5.4\ m/s)}\\\\\theta = Sin^{-1}(0.545)[/tex]

θ = 33°

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:

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

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Answer:

To increase the conductivity of the material.

Explanation:

Generally , the group 4 elements are non conductor but in certain conditions, such as doping or the increase in temperature, they becomes conductor.

The doping is the process of mixing of pentavalent or the trivalent material into tetra valent material in the very small amount, so that the material becomes conductor.

In making a diode we need two types of the materials, n type semiconductor and p type semi conductor.

When the trivalent impurity is added in the tetra valent element, the semiconductor becomes n type because an electron is left for the conduction.

When the pentavalent impurity is added in the tetra valent element, the semiconductor becomes p type because a hole is left for the conduction.

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:

6.24 x 1018 electrons.

Explanation:

So I think C

u = 0.077

Explanation:

Work done by friction is

Wf = ∆KE + ∆PE

-umgx = ∆KE,. ∆PE =0 (level ice surface)

-umgx = KEf - KEi = -(1/2)mv^2

Solving for u,

u = v^2/2gx

= (12 m/s)^2/2(9.8 m/s^2)(95 m)

= 0.077

Kinetic friction is the ratio of the friction force to the normal force experienced by a body in moving state.The coefficient of kinetic friction between the ice and skates is 0.077.

Given-

velocity of the ice skater is 12 m/ sec.

Work done by the friction is the sum of the change of the kinetic energy and the change in potential energy.

[tex]W_{f}=\bigtriangleup KE +\bigtriangleup PE[/tex]

The value for the potential energy will be equal to Zero in this case. Therefore the work done by the friction is,

[tex]W_{f}=\bigtriangleup KE +0[/tex]

Kinetic energy is directly proportional to the mass of the object and to the square of its velocity and work done can be given as,

[tex]W_{f} =u_{f} mgx[/tex]

Here,  [tex]u_{f}[/tex] is friction force, [tex]m[/tex] is mass, [tex]g[/tex] is gravity and x is the distance .

Equate the value of kinetic energy and work done of friction for further result, we get,

[tex]u_{f} mgx=\dfrac{1}{2} \times mv^2[/tex]

[tex]u_{f} =\dfrac{1}{2gx} \times v^2[/tex]

[tex]u_{f} =\dfrac{1}{9.8\times 95} \times 12^2[/tex]

[tex]u_{f} =0.077[/tex]

Hence, the coefficient of kinetic friction between the ice and skates is 0.077.

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Answer:

 [tex]Q=2C[/tex]

Explanation:

From the question we are told that:

Force [tex]F=10000000N[/tex]

Distance [tex]d=60m[/tex]

Where

 [tex]Q_1=Q_2[/tex]

Generally the equation for Force is mathematically given by

 [tex]F=\frac{KQ^2}{r^2}[/tex]

Where

 [tex]K=9*10^9[/tex]

Therefore

 [tex]Q^2=\frac{Fr^2}{K}[/tex]

 [tex]Q^2=\frac{10000000*60^2}{98*10^9}[/tex]

 [tex]Q=\sqrt{\frac{10000000*60^2}{9*10^9}}[/tex]

 [tex]Q=2C[/tex]

Answer:

2.2 s

Explanation:

Using the equation for the period of a physical pendulum, T = 2π√(I/mgh) where I = moment of inertia of leg about perpendicular axis at one point =  mL²/3 where m = mass of man = 67 kg and L = height of man = 1.83 m, g = acceleration due to gravity = 9.8 m/s² and h = distance of leg from center of gravity of man = L/2 (center of gravity of a cylinder)

So, T = 2π√(I/mgh)

T = 2π√(mL²/3 /mgL/2)

T = 2π√(2L/3g)

substituting the values of the variables into the equation, we have

T = 2π√(2L/3g)

T = 2π√(2 × 1.83 m/(3 × 9.8 m/s² ))

T = 2π√(3.66 m/(29.4 m/s² ))

T = 2π√(0.1245 s² ))

T = 2π(0.353 s)

T = 2.22 s

T ≅ 2.2 s

So, the period of the man's leg is 2.2 s

Answer:

Explanation:

the spheres cant be electrons as they will repel each other.

so the ans is D. Atoms

Answer:

D. Atoms

Explanation:

The spheres in this model represents the atoms. So, option (D) is correct answer.

Answer:

C)12150J

Explanation:

KE = (1/2)(m)(v²)

KE = .5*30g(1kg/1000g)*(900m/s)²

KE = 12,150J

Answer:

RIGHT,  SAME SIZE,   VIRTUAL

Explanation:

Plane mirrors comply with the law of reflection where the angle of incidence is equal to the angle of reflection

therefore to complete the sentences:

A plane mirror produces images of objects that have an orientation that is RIGHT __, a size that is _SAME  SIZE____ (compared to that of the object) and a type that is VIRTUAL_____

Answer:

 d = 178.57 10⁻⁹ m

Explanation:

For this exercise we must find the thickness to minimize the reflection, so the interference for the reflection must be destructive.

To find the expression we must take into account, two things:

* When the light goes from an index mordant medium to one with a higher refractive incoe, it undergoes a phase change of 180 (pi radians)

* within the film the wavelength of light is modulated by the index of refraction

           λₙ = λ₀/ n

In this case the light passes from the air to the reflective layer and undergoes a phase change of ∫π rad,  then it is reflected in the film-glass layer where it undergoes another phase change of π rad, therefore the total change of phase is 2π radians, this change is the or changes its value

period of the trigonometric functions, therefore its value does not change

  the expression for destructive interference is

           d sin θ = (me + ½) λₙ

           d sin θ = (m + ½) λ₀ / n

the minimum thickness occurs for m = 0 and if we take perpendicular incidence the sine = 1

          d = λ₀ /2 n

l

et's calculate

          d = 500 10⁻⁹ /( 2  1.4)

         d = 178.57 10⁻⁹ m

The distance covered by the car for the speed of 2.40 m/s² for 15 seconds is 36 meters

To find the distance the given datas are:

Speed = 2.40 m/s²

Time = 15 seconds.

               Distance = Speed × Time.

Substituting the given datas in the formula,

Distance = 2.40 × 15

               = 36 m

The Car went at the distance of about 36 meters.

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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:

10J

Explanation:

KE = (1/2)mv²

100J = (.5)(40kg)v²

v²=(100J)/(20kg)

v²= 5

KE = 5(.5)(4kg)

KE = 10J

A thermal conductor, such as water is the type of material that is good at transferring heat. Option B is correct.

Heat conductors are substances that effectively conduct thermal energy.

The kind of substance that is effective in transferring heat is a thermal conductor, such as water.

Metals have excellent heat conductivity. Heat insulators are substances that poorly conduct thermal energy. Thermal insulators include gases like air and materials like plastic and wood.

Water conducts heat 24.17 times more quickly than air. The kind of substance that is effective in transferring heat is a thermal conductor, such as water.

Hence, option B is correct.

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Answer:

Horizontal Component of Fish's Velocity = 2.6 m/s

Explanation:

In this scenario, we will neglect the effects of the air resistance on the small fish. Since there is no resisting force available in the horizontal direction. Therefore, the horizontal component of the velocity of the fish will remain equal to the horizontal component of the velocity of the seagull and it will remain the same throughout the whole motion.

Horizontal Component of Fish's Velocity = Constant Horizontal Speed of Seagull

Horizontal Component of Fish's Velocity = 2.6 m/s