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4 years ago

Can someone help with these?

Physics

1 answer:

Flauer [41]4 years ago

4 0

Basically, all of these questions use F = ma

m = 80 kg

a = 1.62

Weight = F = 80*1.62 = 129.6

The closest answer is B

Find the mass here on earth

m = F/a

F = 40 kg

a = 9.2

F = 40/9.2 = 4.34

Now take everything to the moon

F = 20 kg

a = ??

m = 4.34

a = F/m = 20/4.34 = 4.6 m/s^2

m = 40 kg

F = 20 N

a = ??

a = F/m = 20N/40kg = 1/2 m/s^2

Comment

All of these depend on F = m*a. None but the first one talk about vertical forces where gravity would play a part. Moving horizontally means that there is no gravitational force if there is no friction. a = 9.8 has nothing to do with the problem.

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Look at pic for question pls help

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B IS YOUR ANSWER.

Soft sound has small amplitude and louder sound has large amplitude. Since, the second wave has large amplitude, it will have the loudest sound.

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3 years ago

A 10-cm-thick aluminum plate (α = 97.1 × 10−6 m2/s) is being heated in liquid with temperature of 475°C. The aluminum plate has

Anuta_ua [19.1K]

Answer:

$T_0 = 338.916 Degree\ celcius$

Explanation:

Given data:

Thickness of aluminium sheet 10 cm

initial temperature = 25 degree celcius

Assumption

Thermal properties remain constant, transfer of heat by radiation is negligible.

from the information given in the question we have

T_S ≈T_∞ , it implies we have h → ∞

from table 4.2 Biot number → ∞ the value of

$\lambda_1 = 1.5708 and A_1= 1.2732$

The fourier number is

$t = \frac{\alpha t}{l^2} = \frac{97.1\times 10^{-6} \times 15}{0.05^2} = 0.5826$

Temperature at center after 15 second of heating

$\theta _{0 wall} = \frac{T_0 - T_{\infity}}{T_i -T_{\infity}} = A_i e^{\lambda_1^2 t}$

$T_0 = T_i -T_{\infity} \times A_i e^{\lambda_1^2 t}$

$T_0 = (25 - 475) 1.2732 e^{-1.5708^2 \times 0.5826} + 475 = 356 degree celcius$

$T_0 = 338.916 Degree\ celcius$

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3 years ago

What is the element with the lowest electronegativity value?

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<h2>Answer: Francium </h2>

Let's start by explaining that electronegativity is a term coined by Linus Pauling and is determined by the <em>ability of an atom of a certain element to attract electrons when chemically combined with another atom. </em>

So, the more electronegative an element is, the more electrons it will attract.

It should be noted that this value can not be measured directly by experiments, but it can be determined indirectly by means of calculations from other atomic or molecular properties of the element. That is why the scale created by Pauling is an arbitrary scale, where the maximum value of electronegativity is 4, assigned to Fluorine (F) and the <u>lowest is 0.7, assigned to Francium (Fr).</u>

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4 years ago

Describe the responses of the human ear to sound waves coming from the

maria [59]

If the sound comes from the right side, the waves reach the right ear before the left ear. if the sound comes from the left side, the waves reach the left ear before the right ear. The difference between the phases of waves reaching both ears is detected by the ears and then interpreted by the brain

8 0

3 years ago

A 220 g mass is on a frictionless horizontal surface at the end of a spring that has force constant of 7.0

Talja [164]

The concept of conservation of energy and harmonic motion allows to find the result for the power where the kinetic and potential energy are equal is:

x = 0.135 cm

Given parameters

The mass m = 220 g = 0.220 kg

The spring cosntnate3 k = 7.0 N / m

Initial displacement A = 5.2 cm = 5.2 10-2 m

To find

The position where the kinetic and potential energy are equal

A simple harmonic movement is a movement where the restoring force is proportional to the displacement, the result of this movement is described by the expression.

x = A cos wt + fi

w² = $\frac{k}{m}$

Where x is the displacement from the equilibrium position, A the initial amplitude of the system, w the angular velocity t the time, fi a phase constant determined by the initial conditions, k the spring constant and m the mass.

The speed is defined by the variation of the position with respect to time.

v = $\frac{dx}{dt}$

let's evaluate

v = - A w sin (wt + Ф)

Since the body releases for a time t = 0 the velocity is zero, therefore the expression remains.

0 = - A w sin Ф

For the equality to be correct, the sine function must be zero, this implies that the phase constant is zero

x = A cos wt

Let's find the point where the kinetic and potential energy are equal.

K = U

½ m v² = m g x

we substitute

½ A² w² sin² wt = g A cos wt

sin² wt = $\frac{2g}{A}$ cos wt

let's calculate

w = $\sqrt{\frac{7}{0.220} }$

w = 5.64 rad / s

sin² 5.64t = 2 9.8 / 0.052 cos 5.64t

sin² 5.64t = 376.92 cos 5.64 t

1 - cos² 5.64t = 376.92 cos 5.64t

cos² 5.64t -376.92 cos564t -1 = 0

we make the change of variable

x = cos 5.64t

x²- 376.92 x - 1 = 0

x = 0.026

cos 5.64t = 0.026

Let's find the displacement for this time

x = 5.2 10-2 0.026

x = 1.35 10-3 m

In conclusion Using the concepts of conservation of energy and harmonic motion we can find the result for the could where the kientic and potential enegies are equal is:

x = 0.135 cm

Learn more here: brainly.com/question/15707891

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3 years ago