(Will give Brainliest) Some scientists calculated that a whale can develop 150 kW of power when it is swimming under the water surface at a constant speed 7.77 m/s. Find the resistance force of the water exerted on the whale.

Answer:

M = 1.90 Kg

Explanation:

Given data: mass = 2.5 Kg

radius R = 0.8 m

angular velocity ω = 1.5 rad/s

Angular momentum L =0.5×Iω^2

Where, I  is the moment of inertia of the spinning disc.

I = 0.5MR^2

I = 0.5×2.5×0.8^2

I = 0.8 Kg/m^2

Then L = 0.5×0.8×1.5^2 = 0.8×2.25 = 0.9 Kg-m^2/sec

Let unknown mass be M

New mass of disc = (2.5+M) Kg, R = 0.8 m

New I = 0.5(2.5+M)(0.8)^2

Since, angular momentum is conserved

Angular momentum before = angular momentum after

0.5×0.5(2.5+M)(0.8)^2×(1.13)^2 = 0.9

Solving for M we get

0.204304(2.5+M)=0.9

M = 1.90 Kg

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: A. Ar

Explanation: not anything else besides Ar

Answer: 3.13 m

Explanation:

Given

mas of the ball is m=10 kg

The ball rolls down a vertical distance of 5 m

Spring constant of spring is [tex]k=100\ N/m[/tex]

Here, the potential energy of the ball converted into kinetic energy which in turn converts into elastic potential energy

[tex]\Rightarrow mgh=\frac{1}{2}kx^2\quad [\text{x=compression in the spring}]\\\\\Rightarrow 10\times 9.8\times 5=\frac{1}{2}\cdot 100\cdot x^2\\\Rightarrow x=\sqrt{9.8}\\\Rightarrow x=3.13\ m[/tex]

Thus, the spring compresses by 3.13 m.

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:

B. 2 hours

Explanation:

45 miles an hour times 2 is 90 miles in 2 hours

Answer:

B. 2 Hours

Explanation:

If your going at a constant speed of 45 miles per hour then, it will take two hours because 45x2 is 90. and if you divided 90 and 45, you will get 2.

Explanation:

Let omega = angular velocity (in rad/s). Then

omega = (# of oscillations)/(6 s)

= (30 osc)/(6 s) = 5 osc/s

We need to convert this to rad/s:

omega = (5 osc/s)(2π rad/osc)

= 10π rad/s

= 31.4 rad/s

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

#SPJ2

Answer:

Explanation:

The law is about how object will be deformed when certain amount force is  applied. Elastic limit is a point where object will not return its previous shape after being deformed

Answer:

False.

Explanation:

The voltage of a disconnected charged capacitor decreases when the plates are brought closer together because the capacitance is inversely proportional to the area. If the area between plates decreases, its capacitance increases and vice versa. There is direct relationship between voltage of a disconnected charged capacitor and plates. If the distance between plates decreases, the voltage of a disconnected charged capacitor is also decreases while on the other hand, if the distance between plates increases, the voltage of a disconnected charged capacitor is also increases.

Answer:

gravity

Explanation:

I don't know what the explanations would be

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:

B,C,D

Explanation:

Ap3X

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:

Option A

Explanation:

The graph for this problem must depict the following ""Increased allocation of resources to reproduction relative to growth diminished future fecundity."

Hence, the survivor ship must be on the Y axis and the resources on the X axis.

Here the resources include the number of seeds produced.

hence, the higher is the number of seeds (resource), the lower is the survivorship (future fecundity)

Hence, option A is correct

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:

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:

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:

Gy = 3.14x10⁻⁴ Gy

Explanation:

To get the dose in Gy we need to use the following expression:

Gy = E / m  (1)

Where:

Gy: dose

E: energy absorbed per atom

m: mass of the human body.

We don't have the energy per atom, but we can calculate that by following the next procedure.

First, let's determine the number of atoms of potassium in our body. For that we need to determine the moles in the 140 g of potassium, with the molecular mass and then, use the avogadro's number:

moles = m/MM

moles = 140 / 39.1 = 3.58 moles

N° atoms = 3.58 * 6.02x10²³ atoms = 2.16x10²⁴ atoms of K.

The abundance of the ⁴⁰K is 0.012% so the atoms of this isotope would be:

N = 2.16x10²⁴ * (0.012/100) = 2.59x10²⁰ atoms of ⁴⁰K.

With this number, and the half life rate, we can determine the number of decay atoms in a year (λ) using the following expression:

λ = ln2 / t(1/2)

λ = ln2 / 1.3x10⁹ = 5.33x10⁻¹⁰ year⁻¹

This number, multiplied by the number of atoms:

R = 5.33x10⁻¹⁰ * 2.59x10²⁰ = 1.38x10¹¹ atoms/year

Now, each atom of K gives an average energy of 1 MeV, so with the atoms we have:

E = 1.38x10¹¹ * 1x10⁶ eV = 1.38x10¹⁷ eV

This value can be expressed in Joules so:

E = 1.38x10¹⁷ eV * (1 J / 6.24x10¹⁸ eV) = 0.022 J

Finally, we can use (1) to get the dose in Gy:

Gy = 0.022 / 70

Hope this helps

Answer:

2 m/s²

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 0 m/s

Final velocity (v) = 12 m/s

Time (t) = 6 s

Acceleration (a) =?

The acceleration of the player can be obtained as follow:

v = u + at

12 = 0 + (a × 6)

12 = 6a

Divide both side by 6

a = 12 / 6

a = 2 m/s²

Thus, the acceleration of the player is 2 m/s²

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:

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:

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:

E = 1.711 MeV

Explanation:

From the law of the conservation of energy:

[tex]K.E_{e}+K.E_p + E_{e}+E_{p} = 2 E[/tex]

where,

[tex]K.E_e=K.Ep=[/tex] the kinetic energy of positron and electron = 1.2 MeV

[tex]E_e=E_p =[/tex] Rest energy of the electron and the positron = 0.511 MeV

E = Energy of Photon = ?

Therefore,

[tex]1.2\ MeV + 1.2\ MeV + 0.511\ MeV + 0.511\ MeV = 2E\\\\E = \frac{3.422\ MeV}{2}\\\\[/tex]

E = 1.711 MeV

Answer:

Explanation:

it would be 3 because ju divide 12 by 4

Answer:

F = 51.3°

Explanation:

The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:

[tex]F = Parallel\ Component\ of\ Weight\ of\ Wagon= WSin\theta\\[/tex]

where,

W = Weight of Wagon = 150 N

θ = Angle of Inclinition = 20°

Therefore,

[tex]F = (150\ N)Sin\ 20^o[/tex]

F = 51.3°