Which of the following is an example of an insulator?
A- metal spoon
B- weather stripping
C-iron skillet
D-glass​

Answer:

He concluded the fact that most alpha particles went straight through the foil is evidence for the atom being mostly empty space. A small number of alpha particles being deflected at large angles suggested that there is a concentration of positive charge in the atom.

Explanation:

Answer:

0.287 m

Explanation:

The velocity of block A when it reaches block B is:

KE₀ = KE + W

½ mv₀² = ½ mv² + Fd

½ mv₀² = ½ mv² + mg μ d

v₀² = v² + 2g μ d

v² = v₀² − 2g μ d

v² = (10 m/s)² − 2 (9.8 m/s²) (0.3) (4 m)

v = 8.75 m/s

The coefficient of restitution is 0.6, so the relative velocity between A and B after the collision is:

e = |Δv after| / |Δv before|

0.6 = Δv / (8.75 m/s)

Δv = 5.25 m/s

Momentum is conserved, so the speed of block B after the collision is:

m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂

(15 kg) (8.75 m/s) + (10 kg) (0 m/s) = (15 kg) (v) + (10 kg) (v + 5.25 m/s)

131.2 m/s = 25v + 52.5 m/s

25v = 78.7 m/s

v = 3.15 m/s

Energy is conserved, so the compression of the spring is:

KE = EE + W

½ mv² = ½ kd² + Fd

½ mv² = ½ kd² + mg μ d

½ (10 kg) (3.15 m/s)² = ½ (1000 N/m) d² + (10 kg) (9.8 m/s²) (0.3) d

49.6 = 500 d² + 29.4 d

0 = 500 d² + 29.4 d − 49.6

d = [ -29.4 ± √(29.4² − 4(500)(-49.6)) ] / 1000

d = (-29.4 ± 316.2) / 1000

d = 0.287 m

Answer:

Explanation:

given

Mass of cart= 150kg

mass of each wheel=45kg

mass of 4 wheels= 180kg

angle of the track=  17 ∘

distance of track= 27m

The height  of the tracl is calculated thus:

sin 17° = h / 27

h = sin 17*27

h=7.89m

"Potential energy at top = kinetic energy of cart and wheels at bottom + rotational energy of wheels at bottom "

1. Potential energy at top= (M+4m)gh

2. kinetic energy of cart and wheels at bottom= 1/2 (M+4m) v²

3. rotational energy of wheels at bottom= 4(1/2 Iω²)

The total is expressed as

(M+4m)gh = 1/2 (M+4m) v² + 4(1/2 Iω²) -------------1

we know that  I = mr² / 2

Put I= mr² / 2

(M+4m)gh = 1/2 (M+4m)v² + 4(1/2 (mr² / 2) ω²)

(M+4m)gh = 1/2 (M+4m)v² +  m r² ω²

we know that  v²= r² ω²

(M+4m)gh = 1/2 (M+4m)v² +  m v²

(M+4m)gh = v² (M/2 + 2m + m)

(M+4m)gh = v² (M/2 + 3m)

v = √[(M+4m)gh / (3m + M/2)]

v = √[(150 + 4*45) * 9.8 m/s² * 7.89 m / (3*45 + 150/2)]

v=√25516.26/142.5

v=√179.06

v = 13.4 m/s

Answer:

[tex] \frac{1}{2} \times m \times {v}^{2} \\ \frac{1}{2} \times m \times {2}^{2} \\ 2 \times m[/tex]

I dont the child mass...you should substitute that value to (m)

then you can get your answer

Answer:

F_{players} = 2528.4[N]

Explanation:

To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body must be equal to the product of mass by acceleration.

On the sled act two forces, the force of friction and The Force executed by the football players.

The movement of the football players will be taken as positive, while the friction will be taken as negative, since it is opposed to the movement of the sled.

ΣF = m*a

where:

F = force [N]

m = mass [kg]

a = acceleration = 0.580 [m/s²]

[tex]F_{players} - f_{friction} = m*a[/tex]

The friction force is defected as the coefficient of friction by the normal force, the normal force on a horizontal surface can be calculated as the product of mass by gravitational acceleration.

[tex]f_{friction}=0.8*(300*9.81)\\f_{friction}=2354.4[N][/tex]

Now we can calculate the force exerted by the players.

[tex]F_{players}-2354.5=300*0.580\\F_{players}=2528.4[N][/tex]

Answer:

yess

Explanation:

Answer:

yes me

Answer:

The linear (tangential) speed of a passenger is 0.4188 m/s

The distance traveled by the person in 5 minutes ride is 125.64 m

Explanation:

Given;

radius of the Ferris, r = 12 m

1 revolution per 3 minutes, [tex]\omega = \frac{2\pi (radian)}{3\ (minutes)} *\frac{1\ minute}{60 \ seconds} = 0.0349 \ rad/s[/tex]

The linear (tangential) speed of a passenger is given by;

v = ωr

v = (0.0349)(12)

v = 0.4188 m/s

The distance traveled by the person in 5 minutes ride is given by;

d = vt

d = (0.4188)(5 x 60)

d = 125.64 m

Answer:

Charge, [tex]q=7.68\times 10^{-12}\ C[/tex]

Explanation:

It is given that,

The number of electron in a RBCs, [tex]n=4.8\times 10^7[/tex]

We need to find the total charge of these electrons in the red blood cell. Let it is q. Using the quantization of charge as follows :

q = ne

e is the change on electron

[tex]q=4.8\times 10^7\times 1.6\times 10^{-19}\\\\q=7.68\times 10^{-12}\ C[/tex]

So, the net charge is [tex]7.68\times 10^{-12}\ C[/tex].

Answer:

When the projectile is launched straight up, there isn't a horizontal ... The initial acceleration was 9.8 m/s2 pointing up, so the acceleration at any other point should be the same.

Explanation:

Hope it helped =)

The maximum altitude that the cannonball will reach if fired straight up at a speed of 25 m/s is; 31.86 m

According to the question;

The cannonball is fired straight up at a speed of 25 m/s

Additionally, the cannonball is fired against the force of gravity.

Consequently, the motion is in the opposite direction of the acceleration due to gravity.

From the equation of motion;

At the maximum altitude, V = 0.

The maximum altitude that it will reach is;

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Answer:

Explanation:

CANT SEE ITS TOO PIXELATED

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 5000 × 5

We have the final answer as

Hope this helps you

You are most likely going through depression. I think you should talk to someone, it could help or try talking to one of us on brainly. I hope you feel better eventually. Your life is valuable try and realize that.

Answer:

You don't need a reason to be sad. It sound as though you are suffering from depression. I understand that. Last year I thought about taking my life, but my parents found out how I was feeling and have been so supportive. Something My mom said that really got to me was, if you killed yourself, who would find you. For me it would have been my little sister. I would have scared her for life. I have come a long way since then, I am doing family therapy, as well as persona, therapy. If you are feeling sad, there is a hotline you can text rather than call. Let them talk you out of it. They won't call anyone if you don't ask them to. Talking to a complete stranger helps, they don't know anything about you so they can't judge you. Also try listening to music, find an artist that you can relate to. For me I like listening to NF when I am feeling down. It helps.

Answer:

C

Explanation:

Answer:

Hip-hop Dancing

Explanation:

Aerobic exercises are light (somewhat, a more accurate word would be bearable) workouts that you can endure over long periods of time. Anaerobic workouts describe workouts that require sudden burst of energy, like the ones you seen in most forms of dance, such as Hip-hop dance.

Hope this helps!

Answer:

61.6886 kg

Explanation:

Answer:

61 kg

Explanation:

there ya go hope this was useful

Answer:Well toasting it makes it a solid so that’s a chemical change that happens! Hope this helped!

Answer:

5m/s

Explanation:

Distance/Time= Speed

D/T=S

15/3=S

5=S

The correct option is A i.e.  Van der Waals forces.

what is Van der Waals forces?

Van der Waals forces are weak intermolecular forces that are depending on atom or molecule distance. Interactions between uncharged atoms/molecules produce these forces.

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#SPJ2

Answer:

[tex]\mu_s=0.51[/tex]

Explanation:

Coefficient of friction

The static coefficient of friction is a measure of the force needed to start moving an object from rest along a rough surface.

It's calculated as:

[tex]\displaystyle \mu_s=\frac{F_r}{N}[/tex]

Where Fr is the friction force and N is the normal force exerted by the surface over the object.

In the absence of any other vertical force, the normal is equal to the weight of the object:

[tex]N = W = m.g[/tex]

The box has a mass of m=80 Kg, thus the normal force is:

[tex]N = 80\ Kg * 9.8\ m/s^2[/tex]

N = 784 N

The student needs to push with a force of 400 N to make the box move. That is the force that barely outcomes the friction force. Thus:

[tex]F_r=400\ N[/tex]

Calculating the coefficient:

[tex]\displaystyle \mu_s=\frac{400}{784}[/tex]

[tex]\mathbf{\mu_s=0.51}[/tex]

Answer:

720 V

Explanation:

Given that,

The number of turns in primary coil, N₁ = 60

The number of turns in secondary coil, N₂ = 360

The input rms voltage, V₁ = 120 V

We need to find the output rms voltage of the secondary coil . The relation between number of turns in primary coil - secondary coil to the input rms voltage to the output rms voltage is given by :

[tex]\dfrac{N_1}{N_2}=\dfrac{V_1}{V_2}\\\\V_2=\dfrac{N_2V_1}{N_2}\\\\V_2=\dfrac{360\times 120}{60}\\\\V_2=720\ V[/tex]

Answer:

3

Explanation:

• initial horizontal speed: 51.0 m/s

• initial vertical speed: 24.0 m/s

• initial speed: √((51.0 m/s)² + (24.0 m/s)²) ≈ 56.4 m/s

• angle: tan(θ) = (24.0 m/s) / (51.0 m/s)   →   θ ≈ 25.2º

Using Pythagoras, the initial speed and the launch angle of the cannon ball are 56.36 m/s and 25.20° respectively.

The initial speed can be obtained using length of the diagonal :

v² = 51² + 24²

v² = 2025

v = √3177

v = 56.36 m/s

The launch angle, θ :

θ = tan¯¹(24/51)

θ = tan¯¹(0.4705)

θ = 25.20°

Hence, the angle of launch is 25.20°

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Answer:

x is vertical and y is horizontal

Explanation:

Answer:

a. 186.2 J b. 8.63 m/s c. 190 m d. 43.2 s e. 186.2 J

Explanation:

a. From conservation of energy, the potential energy loss of block = kinetic energy gain of the block.

So, U + K = U' + K' where U = initial potential energy of block = mgh, K = initial kinetic energy of block = 0, U' = final potential energy of block at bottom of curve = 0 and K' = final kinetic energy of block at bottom of curve.

So, mgh + 0 = 0 + K'

K' = mgh where m = mass of block = 5 kg, g = acceleration due to gravity = 9.8 m/s², h = initial height above the ground of block = radius of curve = 3.8 m

So, K' = 5 kg × 9.8 m/s² × 3.8 m = 186.2 J

b. Since the kinetic energy of the block K = 1/2mv²  where m = mass of block = 5 kg, v = velocity of block at bottom of curve

So, v = √(2K/m)

= √(2 × 186.2 J/5 kg)

= √(372.4 J/5 kg)

= √(74.48 J/kg)

= 8.63 m/s

c. To find the stopping distance, from work-kinetic energy principles,

work done by friction = kinetic energy change of block.

So ΔK = -fd where ΔK = K" - K' where K" = final kinetic energy = 0 J (since the block stops)and K' = initial kinetic energy = 186.2 J, f = frictional force = μmg where μ = coefficient of kinetic friction = 0.02, m = mass of block = 5 kg, g = acceleration due to gravity = 9.8 m/s² and d = stopping distance

ΔK = -fd

K" - K' = - μmgd

d = -(K" - K')/μmg

Substituting the values of the variables, we have

d = -(0 J - 186.2 J)/(0.02 × 5 kg × 9.8 m/s²)

d = -(- 186.2 J)/(0.98 kg m/s²)

d = 190 m

d. Using v² = u² + 2ad where u =initial speed of block = 8.63 m/s, v = final speed of block = 0 m/s (since it stops), a = acceleration of block and d = stopping distance = 190 m

So, a = (v² - u²)/2d

substituting the values of the variables, we have

a = (0² - (8.63 m/s)²)/(2 × 190 m)

a = -74.4769 m²/s²/380 m

a = -0.2 m/s²

Using v = u + at, we find the time t that elapsed while the block is moving on the horizontal track.

t = (v - u)/a

t =(0 m/s - 8.63 m/s)/-0.2 m/s²

t = - 8.63 m/s/-0.2 m/s²

t = 43.2 s

e. The work done by friction W = fd where

= μmgd where f = frictional force = μmg where μ = coefficient of kinetic friction = 0.02, m = mass of block = 5 kg, g = acceleration due to gravity = 9.8 m/s² and d = stopping distance = 190 m

W = 0.02 × 5 kg × 9.8 m/s² × 190 m

W = 186.2 J

The potential energy of the loss of the block will be equal to the kinetic energy gain. The kinetic energy of the block is 186.2 J at the bottom of the curved surface.

The potential energy of the loss of the block will be equal to the kinetic energy gain.

So,

[tex]U = mgh[/tex]

Where,

[tex]U[/tex] - potential energy

[tex]m[/tex] - mass of block =  5 kg

[tex]g[/tex] - gravitational  acceleration = 9.8 m/s²

[tex]h[/tex] = height = radius of curve = 3.8 m

Put the values in the formula,

[tex]U = 5 \times 9.8 \times 3.8 \\\\ U = 186.2 \rm \ J[/tex]

Therefore, the kinetic energy of the block is 186.2 J at the bottom of the curved surface.

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Answer:

A law is defined as a description or a statement given after an observed phenomenon. A theory is a simplification of certain observational data as to how and why it happened.

Explanation:

I hope this helped solve your question.

Answer:

C. Lighting is made of atoms

Explanation:

Everything is made of atoms that are, in turn, made out of charged particles. All charged particles come in one of two types: positive and negative (or plus and minus). The minus particles are the electrons, and the plus particles are the much heavier protons which are buried deep in the nucleus.

Answer:

wavelength = 3000 m

Explanation:

We use the formula for the relationship between the speed (c), frequency (v), and wavelength [tex](\lambda)[/tex]:

[tex]c=\lambda\,*\,\nu\\300000000 \,\,m/s = \lambda\,*100000 \,\,1/s\\\lambda \,=\,3000\,\,m[/tex]

Carcinoma refers to a malignant neoplasm of epithelial origin or cancer of the internal or external lining of the body. Carcinomas, malignancies of epithelial tissue, account for 80 to 90 percent of all cancer cases. Epithelial tissue is found throughout the body.

Answer:

A. 7 s ≤ t < 10 s

Explanation:

From Definite Integral Theory and Mechanical Physics we remember that change in position is represented by sum of areas below the curve. According to the graphic, we see that the following condition must be satisfied:

[tex]A_{1}+A_{2} = 0[/tex] (1)

Where:

[tex]A_{1}[/tex] - Change in position from [tex]t = 0\,s[/tex] and [tex]t = 3\,s[/tex], measured in meters.

[tex]A_{2}[/tex] - Change in position from [tex]t = 5\,s[/tex] and [tex]t = T[/tex], measured in meters.

By definitions of triangle, we expand the equation above:

[tex]\frac{1}{2}\cdot (3\,s)\cdot \left(1.2\,\frac{m}{s} \right) -\frac{1}{2}\cdot (T-5\,s)\cdot v = 0\,m[/tex]

[tex]1.8\,m-0.5\cdot T \cdot v +2.5\cdot v = 0[/tex]

And the time is now cleared:

[tex]1.8\,m+2.5\cdot v = 0.5\cdot T\cdot v[/tex]

[tex]T = \frac{1.8+2.5\cdot v}{0.5\cdot v}[/tex]

Where:

[tex]v[/tex] - Final velocity of the cart, measured in meters per second.

[tex]T[/tex] - Time, measured in seconds.

If we know that [tex]v = 1\,\frac{m}{s}[/tex], then the intended instant is:

[tex]T = \frac{1.8+2.5\cdot (1)}{0.5\cdot (1)}[/tex]

[tex]T = 8.6\,s[/tex]

The value does not coincide with the time from the graph.

If we know that [tex]v = 1.5\,\frac{m}{s}[/tex], then the intended instant is:

[tex]T = \frac{1.8+2.5\cdot (1.5)}{0.5\cdot (1.5)}[/tex]

[tex]T = 7.4\,s[/tex]

This value does not coincide with the time from the graph.

If we know that [tex]v = 1.1\,\frac{m}{s}[/tex], then the intended instant is:

[tex]T = \frac{1.8+2.5\cdot (1.1)}{0.5\cdot (1.1)}[/tex]

[tex]T = 8.273\,s[/tex]

This results offer a reasonable approximation, which that the correct answer is A.

The car will return to its position at the time interval of 7 s ≤ t < 10 s. Hence, option (A) is correct.

The change in position is represented by sum of areas below the curve. According to the graphic, we see that the following condition must be satisfied:

A + A' = 0 ..................................................(1)

A is the change in position from t = 0 and t = 3 s, measured in metres.

A' is the change in position from t = 5 and t = T s, measured in metres.

As per the triangle law,

1/2 ×(3 s)(1.2) - 1/2 ×(T - 5)v = 0

1.8 - 0.5T(v) +2.5(v) =0

T = (1.8 + 2.5v)/ (0.5v)

Here, v is the final velocity of cart.

For v = 1 m/s, we have,

T = (1.8 + 2.5(1))/ (0.5(1))

T = 8.6 s

Since, the values do not coincide with the time from the graph, so taking another value, v = 1.5 m/s to obtain the time as,

T = (1.8 + 2.5(1.5))/ (0.5(1.5))

T = 7.4 s

This value does not coincide with the time from the graph.  If we know that , v = 1.1 m/s, then the intended instant is:

T = (1.8 + 2.5(1.1))/ (0.5(1.1))

T = 8.273 s

Thus, we can conclude that the car will return to its position at the time interval of 7 s ≤ t < 10 s. Hence, option (A) is correct.

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Answer:

D

Explanation:

Towels Absorb