A 0.8 kg bead slides on a curved wire, starting
from rest at point A as shown in the figure.
The segment from A to B is frictionless, and
the segment from B to C is rough. The point
A is at height 7.1 m and the point C is at
height 2.5 m with respect to point B.

Find the speed of the bead at B. The acceleration due to gravity is 9.8 m/s2
Answer in units of m/s.

If the bead comes to rest at C, find the change
in mechanical energy due to friction as it
moves from B to C.
Answer in units of J.

Answer:

B. Frequency

Explanation:

Answer:

f = 4.67 cm

Explanation:

Here, we can use the thin lens formula, as follows:

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

where,

f = focal length of lens = ?

p = distance of object from lens = 12.4 cm

q = distance of image from lens = 7.5 cm

Therefore,

[tex]\frac{1}{f} =\frac{1}{12.4\ cm} +\frac{1}{7.5\ cm}\\\\\frac{1}{f} = \frac{1}{4.67\ cm}[/tex]

f = 4.67 cm

Answer: 0.390625 grams

Explanation:

A half-life of an element is the amount of time that it takes for half the mass of the element to decay.

Gold-198 having a half-life of 2.5 days therefore means that every 2.5 days, the mass is cut in half.

If there are 20 days, find out how many half-life periods there are:

= 20 / 2.5

= 8 periods

The half life is:

= Original mass * 0.5^number of half-life periods

= 100 * 0.5⁸

= 0.390625 grams

Answer: [tex]0.00680\ m^3[/tex]

Explanation:

Given

The weight of the object, when submerged in the water is [tex]980\ N[/tex]

When it is submerged in the bromine liquid, it weighs [tex]840\ N[/tex]

Suppose,

[tex]\rho=\text{Density of object}\\\rho_w=\text{Density of water}\\\rho_b=\text{Density of bromine}\\V=\text{Volume of the object}[/tex]

for water,

[tex]\Rightarrow V(\rho -\rho_w)g=980\quad \ldots(i)[/tex]

For bromine

[tex]\Rightarrow V(\rho-\rho_b)g=840\quad \ldots(ii)[/tex]

Divide (i) and (ii)

[tex]\Rightarrow \dfrac{\rho-1000}{\rho-3100}=\dfrac{980}{840}\\\\\Rightarrow 840\rho -840\times 1000=980\rho-980\times 3100\\\\\Rightarrow 140\rho=(3038-840)\cdot 1000\\\\\Rightarrow \rho=15,700\ kg/m^3[/tex]

Put the density value in equation (i)

[tex]\Rightarrow V(15,700-1000)\cdot 9.8=980\\\\\Rightarrow V=\dfrac{100}{14,700}\\\\\Rightarrow V=0.00680\ m^3[/tex]

Answer:

Explanation:

it would be 3 because ju divide 12 by 4

Given :

A gerbil wheel has a radius of 3.2 inches. The gerbil can spin the wheel at a rate of 35 rotations per minute.

To Find :

The angular speed of the wheel in degrees per minute and the linear speed of wheel in inches per minute.

Solution :

Angular speed is given by :

[tex]\omega = 25\ rpm \\\\\omega = 25\times 360^o \ per \ minute\\\\\omega = 9000^o \ per \ minute[/tex]

Now, velocity is given by :

[tex]v = Radius\times \dfrac{RPM}{60\ sec/min}\times 2\pi\ rad/rev\\\\v = 3.2 \times \dfrac{35}{60}\times 2\pi\\\\v = 11.73\ m/s[/tex]

Hence, this is the required solution.

Answer:

a = 0.1962 m/s^2

Explanation:

The magnitude of kinetic friction exerted is given by

[tex]F_k=\mu_kN[/tex]

Where, μ_k= coefficient of kinetic friction= 0.02 and N = reaction force = mg

Where m= mass = 30 Kg and, g is acceleration due to gravity =9.81 m/s^2

F_k=0.02×30×9.81 =5.886 N

Now, since, there is no applied force this kinetic friction force will cause acceleration of the child

⇒ ma = F_k

here, a is the acceleration

⇒30a = 5.886

⇒ a = 0.1962 m/s^2

Answer and Explanation:

The answer is the second answer choice. This is because we humans can rebuild or build memories during the day, it doesn't have to happen via sleep.

The first answer choice IS a reason because you aren't working your brain as hard, so your brain has time to heal. A mouse study suggests that sleep helps restore the brain by flushing out toxins that build up during waking hours.

The third answer choice IS a reason because of the idea of Wish Fulfillment: Sigmund Freud suggested that dreams provide a psychic safety valve to discharge unacceptable feelings. The dream's manifest (apparent) content may also have symbolic meanings (latent content) that signify our unacceptable feelings.

The forth answer choice IS a reason because of the idea of Cognitive Development: Some researchers argue that we dream as a part of brain maturation and cognitive development.

#teamtrees #PAW (Plant And Water)

Answer:

Explanation:

Given that:

To Calculate:

We know that:

We have:

Finding its density:

⟶ Density = 270/360

⟶ Density = 0.75

Hence,

Answer:

(a) The work function is 1.86 eV.

(b) The cut off frequency is 450 THz.

(c) The stopping potential is 1.16 V.

Explanation:

incident wavelength = 620 nm

Kinetic energy, K = 0.14 eV

According to the photoelectric equation

E = W + KE

where, W is the work function, KE is the kinetic energy.

(a) Let the work function is W.

[tex]W = E - KE\\W = \frac{h c}{\lambda }- KE\\W =\frac{6.63\times 10^{-34}\times3\times 10^{8}}{620\times 10^{-9}\times 1.6\times 10^{-19}}-0.14\\\\W =1.86 eV[/tex]

(b) Let the cut off frequency is f.

W = h f

[tex]1.86\times 1.6\times 10^{-19} = 6.63\times 10^{-34}\times f\\f = 4.5\times 10^{14} Hz =450 THz[/tex]

(c) Let the stopping potential is V.

[tex]E = W + eV\\\frac{6.63\times 10^{-34}\times 3\times 10^{8}}{420\times 10^{-9}\times 1.6\times 10^{-19}}=1.8 + eV\\\\V = 1.16 V[/tex]

Answer: [tex]1.67\ V[/tex]

Explanation:

Given

Work function [tex]\phi =1.17\ eV[/tex]

The wavelength of the light is [tex]\lambda =437\ nm[/tex]

Energy associated with this wavelength is

[tex]E=\dfrac{hc}{\lambda}\\\\\Rightarrow E=\dfrac{1.99\times 10^{-25}}{437\times 10^{-9}}\\\\\Rightarrow E=4.553\times 10^{-19}\ J\\\\\Rightarrow E=2.841\ eV[/tex]

Stopping potential is

[tex]V=\dfrac{E-\phi }{e}\\\\\Rightarrow V=\dfrac{\left(2.841-1.17\right)e}{e}\\\\\Rightarrow V=1.67\ V[/tex]

Answer:

9.2 V

Explanation:

The RMS value of an AC is the effective value of a varying voltage or current in DC, that is the equivalent value of the AC which produces the same effect as an DC. For example if a motor is supplied by a 9V RMS voltage, it will rotate as if the voltage applied was 9V DC.

The RMS value is given by:

RMS voltage = Peak voltage * 1/√2

Given that the maximum voltage should not exceed 13 V, this means that the peak voltage is 13 V. The maximum RMS voltage is:

RMS voltage = Peak voltage * 1/√2 = 13 * 1/√2 = 9.2 V

Answer:

  I = 12 A

Explanation:

For this exercise we use the relationship that voltage is proportional to the product of current and resistance

           V = I R

            I = V / R

let's calculate

            I = 120/10

            I = 12 A

Answer:

E = 1.45 x 10⁹ J = 1.45 GJ

Explanation:

According to the law of conservation of energy:

Potential Energy Lost by Satellite = Kinetic Energy + Internal Energy

[tex]mgh = \frac{1}{2} mv^2 + E\\\\E = mgh - \frac{1}{2} mv^2[/tex]

where,

E = Internal Energy = ?

m = mass = 400 kg

g = acceleration due to gravity = 9.81 m/s²

h = height = 500 km = 500000 m

v = speed on ground = 1.6 km/s = 1600 m/s

Therefore,

[tex]E = (400\ kg)(9.81\ m/s^2)(500000\ m)-\frac{1}{2} (400\ kg)(1600\ m/s)^2\\E = 1.962\ x\ 10^9\ J - 0.512\ x\ 10^9\ J[/tex]

E = 1.45 x 10⁹ J = 1.45 GJ

Answer: A. Ar

Explanation: not anything else besides Ar

Answer:

The Formula is

Change in Momentum = Force * Time

or /\P= F/\t

Plug the numbers into that formula,

P=(2,000N)(3S)

Now Multiply

Your Change in Momentum (Or P) would be 6,000N*s

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The magnitude of the change in the car's momentum = 6000 N.s

The rate of change of momentum is equal to impulse . It is the change in the product of mass and velocity of the body or it can be calculated as force times time period for which force is been applied

Change in momentum = impulse(if change occur for few seconds ) = Force * time period

given

Force = 2000 N

mass = 2000 kg

time = 3 seconds

Change in momentum  = 2000 * 3 = 6000 N.s

The magnitude of the change in the car's momentum = 6000 N.s

learn more about Change in momentum  :

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Answer:

B,C,D

Explanation:

Ap3X

Answer:

The correct answer is -

B. The velocity would double (v = 2v).

C. The wavelength would be half (λ = λ/2).

Explanation:

A wave has a speed or velocity that is related to the wavelength of the wave and the frequency of the wave and this relationship can be represented by the following equation-

Wave velocity V = Wavelength (λ) * Frequency (f)

Frequency (f) = Velocity (V) / Wavelength(λ).

The frequency and wavelength are inversely proportional and frequency and velocity are directly proportional to each other.

So, if f = 2f then,

putting value in the formula,

2f = 2v/λ, which means, f = 2v and f = λ/2

when the frequency is doubled, the wavelength will be halved and velocity will be doubled.

Answer:

the charge generated in the circuit​ is 240 C.

Explanation:

Given;

current flowing in the circuit, I = 2A

time of current flow, t = 2 minutes = 2 x 60s = 120 s

The current flowing through a given circuit is defined as the quantity of charge flowing through the circuit in a given time.

[tex]I = \frac{Q}{t} \\\\Q = I t[/tex]

where;

Q is the charge flowing in the circuit

Q = 2 x 120

Q = 240 C

Therefore, the charge generated in the circuit​ is 240 C.

Answer:

a. True

Explanation:

The law of conservation of Energy states that energy cannot be destroyed but can only be converted or transformed from one form to another. Therefore, the sum of the initial kinetic energy and potential energy is equal to the sum of the final kinetic energy and potential energy.

Mathematically, it is given by the formula;

Ki + Ui = Kf + Uf .......equation 1

Where;

Ki and Kf are the initial and final kinetic energy respectively.

Ui and Uf are the initial and final potential energy respectively.

The First Law of Thermodynamics is another way to describe the Law of Conservation of Energy. Typically, the First Law of Thermodynamics states that the change of internal energy of a system is equal to the sum of external work and heat spent on the system.

Mathematically, the First Law of Thermodynamics is given by the formula;

ΔU = Q − W

Where;

ΔU represents the change in internal energy of a system.

Q represents the net heat transfer in and out of the system.

W represents the sum of work (net work) done on or by the system.

Hence, the direction in which any thermodynamic process in nature can spontaneously occur isn't stated by the First Law of Thermodynamics.

Answer:

convex       f = 33 cm

concave     f = -33 cm

Explanation:

In geometric optics the focal length of a lens is given by

         [tex]\frac{1}{f} = ( n-1) \ (\frac{1}{R_2} - \frac{1}{R_1} )[/tex]

where n is the refractive index of the medium, R₁ and R₂   are the focal lengths on each side of the lens.

In this case one of the sides is flat so its focal length is infinite, if the lens is convex the focal length is positive, convergent lens and if it is concave the focal length is negative, divergent lens.

         [tex]\frac{1}{f} = (n-1) \ \frac{1}{R}[/tex]

the refractive index of the glass is n = 1.5

let's calculate

         1 / f = (1.5 -1) 1 / 16.5

         1 / f = 0.03030

          f = 33 cm

convex       f = 33 cm

concave     f = -33 cm

Answer:

I think concave

Explanation:

Answer:

The total resistance is 106 Ω and the current in the circuit is 0.11 A.

Explanation:

Given that,

Voltage of the battery, V = 12 V

Resistors 34 Ω, 42Ω, and 30Ω are connected in series.

The total resistance is given by :}

R = 34 + 42 +30

= 106Ω

Let I is the total current in the circuit. Using ohm's law to find it such that,

[tex]I=\dfrac{V}{R}\\\\I=\dfrac{12}{106}\\\\I=0.11\ A[/tex]

Hence, the total resistance is 106 Ω and the current in the circuit is 0.11 A.

Answer:

0.34 m/s^2

Explanation:

force=mass × acceleration

400 =1200 × acceleration

acceleration=400/1200

=0.34 m/s^2

Answer: c.2

Explanation:

Answer:

The Answer is c. 2

Explanation:

I literally just got done with the quiz

Answer:

D

Explanation:

yes. The shortest object is traveling the fastest.

No,their lengths be used to rank the objects according to their speeds. Because the length of the object is depended on the frame of reference of the observer. Option A is correct.

A frame of reference is a mathematical and physical coordinate system whose origin, direction, and scale are given by a collection of reference points.

Because the length of each item is determined by the observer's frame of reference, If an observer is stationary yet traveling at near light speed, he will feel length contraction.

Otherwise, the length of the items should not alter for everyday pace.A spectator sees four identical objects flying at almost the speed of light.

No,their lengths be used to rank the objects according to their speeds. Because the length of the object is depended on the frame of reference of the observer.

Hence,option A is correct.

To learn more about the frame of reference to refer to the link;

https://brainly.com/question/12222532

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Answer: Higher.

Explanation: The doppler effect essentially. "The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding."

Answer:

P = 756.84 Watts

Explanation:

As the tension is stationary or innitial, T₀ = 31 N, the mean would be:

T₁ + T₂ / 2 = T₀    (1)

T₁ + T₂ = 2 * 31 = 62 N

Now, with the following expression we can determine the linear speed:

V = πWD  (2)

W: angular speed of the wheel  (rev/s)

D: diameter of the wheel (in meters)

W = 1547 rev/min * (1 min/60 s) = 25.78 rev/s

V = π * 25.78 * 0.379 = 30.695 m/s

We also know that:

T₁ / T₂ = exp (μθ)

T₁ = T₂ exp(μθ)   (3)

We already have those values so replacing:

T₁ = T₂ exp(0.3 * 161 * π/180)

T₁ = 2.32T₂   (4)

We can now replace (4) in (1) like this:

T₁ + T₂ = 62 N

2.32T₂ + T₂ = 62

3.32T₂ = 62

T₂ = 18.67 N

Which means that T₁:

T₁ = 2.32(18.67)

T₁ = 43.33 N

Finally, the power can be determined using the following expression:

P = (T₁ - T₂)V  (5)       Replacing we have:

P = (43.33 - 18.67)*30.695

Hope this helps

Answer:

49 kg is the mass of the couch.

Explanation:

GPE = mgh

9800 = m * 10 * 20

9800 = 200m

m = (9800/20) = 49 m

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