A student flexes her neck to 40 degrees from vertical while studying for her final exam. She pivots her head around the upper vertebra, approximated as point P (in the middle of the picture). Her head has a mass of 4.5 kg, and its center of mass is 11 cm away from point P. Her neck muscles are 1.5 cm from point P, measured perpendicular and pulling straight down. How much force do the neck muscles have to exert to keep the head still

Answers

Answer 1

Answer:

[tex]T=208N[/tex]

Explanation:

From the question we are told that:

Neck flex angle [tex]\angle_n=40 \textdegree[/tex]

Head mass [tex]M_h=4.5kg[/tex]

Center of mass [tex]M_c= 11cm[/tex]

Distance of neck from P [tex]d_p=1.5cm[/tex]

Let

[tex]T_g=Gravitational\ force\ torque\\T_{nm}=Tension\ on\ neck\ muscle\ torque[/tex]

Generally the net Torque T_n is mathematically given by

[tex]T_n=0[/tex]

Therefore

[tex]T_g-T_{nm}=0[/tex]

Generally the equation for Torque T is mathematically given by

[tex]T=\frac{M_h*g*l_g}{d_p}[/tex]

where

[tex]l_g=M_c*sin\angle_n[/tex]

[tex]l_g=11*10^{-2}*sin40[/tex]

[tex]l_g=0.07m[/tex]

Therefore

[tex]T=\frac{4.5*9.8*0.07}{1.5*10^{-2}}[/tex]

[tex]T=208N[/tex]


Related Questions

PLEASE HELP ME PLEASE!​

Answers

Answer:

40N

Explanation:

The weight is "how much force of gravity drags this down".

Because we're told that gravity on the Moon exerts 1.6N of force per kg, a 25kg object will weigh:

[tex]F_g = 25kg \cdot 1.6\frac{N}{kg} = 40N[/tex]

It is measured that 3/4 of a body's volume is submerged in oil of density 800kg/m³

Answers

Complete question:

It is measured that 3/4 of a body's volume is submerged in oil of density 800kg/m³. What is the specific gravity of oil?

Answer:

The specific gravity of the oil is 0.8.

Explanation:

Given;

density of the oil, [tex]\rho_o[/tex] = 800 kg/m³

density of water, [tex]\rho_w[/tex] = 1000 kg/m³

The specific gravity of any substance is the ratio of the substance density to the density of water.

Specific gravity of the oil = density of the oil / density of water

Specific gravity of the oil = 800/1000

Specific gravity of the oil = 0.8

Therefore, the specific gravity of the oil is 0.8.

Look at pic for question pls help

Answers

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.

1. The block shown below is being putled to the right on a horizontal table,
Which labeled vectors represent all the forces acting on the block?

Answers

Answer:

E

Explanation:


HELP!!

An electric motor is used to lift an elevator and
occupants (mass = 1.50 x 10kg) to a helght of
15.0 m in 30.0 s at a constant velocity. What is
the power output of the motor? I know the answer I just need someone to show me the steps so I understand how to solve this


Answer: (7.35 x 10^3 W)

Answers

Answer:

[tex]P=7.35\times 10^{3}\ W[/tex]

Explanation:

Given that,

Mass, [tex]m=1.5\times 10^2\ kg[/tex]

It lifts to a height of 15 m in 3 s

We need to find the power of the motor. The formula for power is given by :

[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{1.5\times 10^2\times 9.8\times 15}{3}\\\\P=7.35\times 10^{3}\ W[/tex]

So, the power of the motor is equal to [tex]7.35\times 10^{3}\ W[/tex].

A 0.017-kg acorn falls from a position in an oak tree that is 18.5 meters above the ground. Calculate the velocity of the acorn just before it reaches the ground (rounding your answer to the integer) and its kinetic energy when hitting the ground (rounding your answer to the nearest tenth).

Answers

Answer:

The velocity and translational kinetic energy of the acorn when hitting the ground are approximately 19 meters per second and 3 joules, respectively.

Explanation:

Let suppose that the acorn is a conservative system. By Principle of Energy Conservation, we understand that initial potential gravitational potential energy ([tex]U_{g}[/tex]), in joules, which is related to initial height above the ground, is equal to the final translational kinetic energy ([tex]K[/tex]), in joules, related to the instant just before hitting the ground. Let suppose that ground has a height of zero. That is:

[tex]U_{g} = K[/tex] (1)

[tex]m\cdot g \cdot h = \frac{1}{2}\cdot m \cdot v^{2}[/tex] (1b)

Where:

[tex]m[/tex] - Mass, in kilograms.

[tex]g[/tex] - Gravitational acceleration, in meters per square second.

[tex]h[/tex] - Height, in meters.

[tex]v[/tex] - Speed, in meters per second.

If we know that [tex]m = 0.017\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]h = 18.5\,m[/tex], then the velocity and the translational kinetic energy of the acorn just before hitting the ground is:

[tex]m\cdot g \cdot h = \frac{1}{2}\cdot m \cdot v^{2}[/tex]

[tex]v = \sqrt{2\cdot g \cdot h}[/tex]

[tex]v \approx 19.049\,\frac{m}{s}[/tex]

[tex]K = \frac{1}{2}\cdot m\cdot v^{2}[/tex]

[tex]K = 3.084\,J[/tex]

The velocity and translational kinetic energy of the acorn when hitting the ground are approximately 19 meters per second and 3 joules, respectively.

Just as optical astronomers observe the visible light emitted by objects such as stars and galaxies, radio astronomers can also observe the radio waves emitted by these objects, as well as the radio waves emitted by gas and dust. However, radio telescopes are different from optical telescopes in important ways. In general, compared to optical telescopes, radio telescopes are larger. more curved. more expensive. smaller. This is because

Answers

Answer:

Radio telescopes are LARGER than optical telescopes and this is because radio wavelengths  are much longer than optical wavelengths

Explanation:

In general radio telescopes are LARGER than optical telescopes and this is because radio wavelengths  are much longer than optical wavelengths.

The main difference between radio telescopes and other telescopes especially optical telescopes is based on size and wavelength of both telescopes  

PLEASE HELP!

how am i supposed to label a graph using the points from the protractor?

Answers

Answer:

srghgddggjjjkkkk

Explanation:

fhhgxxxxxxxx3

errghydhi

Why did the “yielders” conform in Asch’s experiment?

Answers

Answer:

Asch's experiment showed that about 75% of people were "yielders" who conformed and 25% were "independent" who didn't conform. Asch concludes that people ignored reality and gave an incorrect answer in order to follow the rest of the group.

PLEASE HELP!!! WILL GIVE 30 POINTS!! HAS TO BE CORRECT!


The picture below shows a solar event in the sun's atmosphere.


Which of these events is most likely to occur as a result of the solar event pictured above?


Disruption to electricity power grid

Less aurora activity at the poles

The sun's photosphere would be blocked

The sun's magnetic effect would decrease

Answers

Answer:

the answer is A . Disruption to electricity power grid :)

Explanation:

Determine the potential difference between the ends of the wire of resistance 5 Ω if 720 C passes through it per minute.

Answers

Answer:

The potential difference between the ends of a wire is 60 volts.

Explanation:

It is given that,

Resistance, R = 5 ohms

Charge, q = 720 C

Time, t = 1 min = 60 s

We know that the charge flowing per unit charge is called current in the circuit. It is given by :

I = 12 A

Let V is the potential difference between the ends of a wire. It can be calculated using Ohm's law as :

V = IR

V = 60 Volts

So, the potential difference between the ends of a wire is 60 volts. Hence, this is the required solution.

Jill doubled the force acting on an object, yet she kept the acceleration constant or unchanged.
How did she do this?

Answers

Answer:

Mass doubles

Explanation:

Since F = ma, and given that the acceleration stayed constant, the mass must have changed. (Assuming thatt when the problem states the force doubles, they mean the net force doubles). Note, that the mass does not have to change if the acceleration is zero.

How much kinetic energy does a 0.30-kg stone have if it is thrown at 44 m/s?
O 440J
O 510 J
O 580J
0 290

Answers

Answer:

0 290

Explanation:

Answer:

290

Explanation:

the reason is that the formula for kinetic energy is half m×v².

you divde half by 0.30 multiply by 44×44

you get 290.4

then you round it to significant figures to get 290

An electron moves through a region of crossed electric and magnetic fields. The electric field E = 3059 V/m and is directed straight down. The magnetic field B = 1.14 T and is directed to the left. For what velocity v of the electron into the paper will the electric force exactly cancel the magnetic force?

Answers

Answer:

v = 2683.33 m/s

Explanation:

The magnetic force and the electric force on the electron must be the same, in order for them to cancel each other:

[tex]Electric\ Force = Magnetic\ Force\\Eq = qvBSin\theta \\\\v = \frac{E}{BSin\theta}[/tex]

where,

v = velcoity of electron = ?

E = Electric Field = 3059 V/m

B = Magnetic Field = 1.14 T

θ = Angle between velocity and magnetic field = 90°

Therefore,

[tex]v = \frac{3059\ V/m}{(1.14\ T)Sin90^o}[/tex]

v = 2683.33 m/s

The Image shows a magnetic field around the poles of a magnet. Identify the areas where the magnetic force is the strongest.
N

Answers

Answer:

strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.

Explanation:

The lines of magnetic force are drawn so that the density of lines is proportional to the intensity of the magnetic field.

Therefore, the sections where the magnetic field is strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.

A cell membrane consists of an inner and outer wall separated by a distance of approximately 10nm10nm. Assume that the walls act like a parallel plate capacitor, each with a charge density of 10−5C/m2, and the outer wall is positively charged. Although unrealistic, assume that the space between cell walls is filled with air.
1. What is the magnitude of the electric field between the membranes?
A. 1×10^−15N/C
B. 5×10^−5N/C
C. 1×10^6N/C
D. 9×10^−2N/C
2. What is the magnitude of the force on a Ca++ ion between the cell walls?
A. 4×10^−13N
B. 4×10^−12N
C. 2×10^−12N
D. 2×10^−11N
3. What is the potential difference between the cell walls?
A. 1×10^7V
B. 1×10^−2V
C. 6×10^−3V
D. 10V
4. What is the direction of the electric field between the walls?
A. Toward the outer wall.
B. Parallel to the walls.
C. Toward the inner wall.
D. There is no electric field.
5. If released from the inner wall, what would be the kinetic energy of a 3fC charge at the outer wall? 1fC=10^−15C.
A. 3×10^−14J
B. 3×10^−17J
C. 3×10^−8J
D. 3×10^−2J

Answers

Answer:

the correct answue are  B, A, C, C, B

Explanation:

1) The electric field is requested, let's approximate the membrane by a parallel plate with surface charge density

         E = [tex]\frac{\sigma }{2 \epsilon_o }[/tex]

         E = [tex]\frac{ 10^{-5}}{2 \ 8.85 \ 10^{-12}}[/tex]

         E = 5.65 10⁵ N / C

the correct answer is B

2) A calcium ion has two positive charges, so the force applied by each side of the membrane (plate)

         F = q E

         F = 2  1.6 10⁻¹⁹  5.65 10⁵

         F = 1.8 10⁻¹³ N

the total force is the sum of the force of each membrane and the two forces go to the same side

         F = total = 2 F

         F_total = 3.6 10⁻¹³ N

the correct answer is A

3) the field and the electric potential are related

          ΔV = - E s

          ΔV = - 5.65 10⁵  10 10⁻⁹

          ΔV = - 5.65 10⁻³ V

          the correct answer is C

4) In the exercise they indicate that the outer wall has a positive charge, therefore, as they indicate that we approximate the system to a capacitor, the inner wall must be negatively charged.

The electric field goes from the positive to the negative charge, which is why it goes from the outer wall to the inner wall

the correct answer is C

5) For this part we use conservation of energy

starting point. On the inside wall, brown

            Em₀ = U = qV

final point. On the outside

             Em_f = K

energy is conserved

           Em₀ = Em_f

           q V = K

            K = 3 10⁻¹⁵  5.65 10⁻³

            K = 1.7 10⁻¹⁷ J

the correct answer is B

What characteristic helps us determine
the temperature of a star?
A. shape
B. texture
C. color

Answers

Answer:

I would say color.

Explanation:

Because for me most of the time the warm color mean It hot. and the cool color most likily to mean cold  

Answer:

Color

Explanation:

The temperature of a star is determined by the color. lol :)

4 points
Bonus: We know that a huge star went supernova in our area a long time
ago because of the large amount of
on earth.
Water
Oxygen
Iron
Carbon

Answers

Answer: i may not be 100% accurate but i believe it is iron, there is a fire work that uses iron to shine a certain way and is found on stars.

what mass of water is required to absorb 4.7 x 10 to the 5th power J of energy from a car engine while the temperature increases from 298K to 355 K


HELPPPPP

Answers

I would answer but the other guy got here first and I don’t know the answer sorry

The scanning process and magnetic lenses used in a scanning electron microscope often results in fair to poor resolution and "fuzzy" images.
(A)True
(B)False

Answers

Answer:

(B)False is the answer.

Explanation:

Water cam form large dewdrops in nature. How would droplets made of isopropyl alcohol instead of water be different?

Answers

Answer:

Isopropyl alcohol would form smaller droplets because it has a lower surface tension than water has.

Explanation:

list some application of atmospheric pressure?​

Answers

Answer:

Drinking straw, syringe, Dropper, vacuum, etc.

Explanation:

example of kinetic energy into heat energy

Answers

Answer:

The kinetic energy of large objects can be converted into this thermal energy.

Explanation:

For example, if you drop a water balloon onto the ground, its kinetic energy is converted mostly to thermal energy. If the balloon weighs 1 kilogram and you drop it from about 2 meters, it will heat up by less.

A Newtonian fluid with a viscosity  drains through the space between two large parallel plates as shown in the figure. The gap distance between the plates is 2b. Obtain relations for the shear stress distribution, shear stress at the walls, velocity profile and volumetric flow rate assuming laminar flow and negligible end effects. You can begin the derivations by considering that vz=vz(x) only and pressure at the inlet and outlet is atmospheric.

Answers

Answer:

well

Explanation:

basically it's like

1.00 x 100 kg of clear liquid (specific heat
capacity = 5.11 x 102 J/kg•°C) at a temperature
of 15.0°C gains 3.33 x 10 J of heat. What is the
final temperature of the liquid? (Assume the
melting point is less than 15.0°C and the boiling
point is greater than 62.0°C.)

Answers

Answer:

No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a ... to change 1 kg of liquid water at the normal boiling point (100ºC at atmospheric pressure) to steam (water vapor).

The melting point of lead is 327.3o C. Assume the final temperature of the system is T. Then the amount of energy released by the lead as it solidifies is. ΔQ = mleadLlead = 0.09 kg*(2.45*104 J/kg) = 2205 J

Which segments show changes of state that absorb heat? Check all that apply.

B–C
C–D
D–C
D–E
E–F

Answers

Answer:

B-C

D-E

Explanation:

Trust

Answer:

B-C and D-E are correct

Explanation:

Free use of uniforms and socialization with classmates are possible advantages of ? A.)
dual sports B.)community-based sports programs C.)individual sports D.) school-based sports programs​

Answers

The answer is B community based sports program

Answer:

its d

Explanation:

Which of the following is the most important difference between a permanent magnet and a electromagnet

Answers

Answer:

Explanation: the major difference between an electromagnet and permanent magnet is that the former can have a magnetic field when electric current flows through it and disappears when the flow of the current stops. ... It will always displays the magnetic behaviour.

The light ray is traveling from Acrylite into air. The refractive index for air is 1.00. If the angle of incidence and the angle of refraction are known, how could you determine the refractive index of Acrylite?

Answers

Answer:

Refraction. A light ray traveling through some plastic has a frequency of 5.5 x 1014 Hz. It is ... making an angle of 32° with the normal to the interface; it passes through the ... [5 points] (a) What is the refractive index of the glass? ... What you do know is the wavelength of the light in glass, 321 nm, and you know the frequency.

Explanation:

The refractive index of Acrylate is determined as: ratio of sine of incident angle to  sine of refractive angle.

What is Snell's law?

The relationship between the angles of incidence and refraction for light or other waves flowing through a border between two different isotropic media, such as water, glass, or air, is described by Snell's law, a formula.

The amount a light ray bends as it travels through different media is measured by the refractive index.

Given that: The refractive index for air is 1.00.

Let the angle of incidence from medium air to Acrylate  is = i

the angle of refraction  from medium air to Acrylate  is = r.

Let the refractive index  for Acrylate  = n.

Then according to Snell's law:

1×sini = n× sinr

n = sini/sinr.

Hence,  the refractive index of Acrylate is ratio of sine of incident angle to  sine of refractive angle.

Learn more about  Snell's law here:

https://brainly.com/question/2273464

#SPJ2

What is the approximate size of the Earth's magnetic field? (dont ask me to specify thats what the question is and im as confused as heck too)

Answers

Answer:

The Earth's magnetic field intensity is roughly between 25,000 - 65,000 nT (.25 -.65 gauss).

Explanation:

To measure the Earth's magnetism in any place, we must measure the direction and intensity of the field. The Earth's magnetic field is described by seven parameters. These are declination (D), inclination (I), horizontal intensity (H), the north (X), and east (Y) components of the horizontal intensity, vertical intensity (Z), and total intensity (F). The parameters describing the direction of the magnetic field are declination (D) and inclination (I). D and I are measured in units of degrees, positive east for D and positive down for me. The intensity of the total field (F) is described by the horizontal component (H), vertical component (Z), and the north (X) and east (Y) components of the horizontal intensity. These components may be measured in units of gauss but are generally reported in nanoTesla (1nT * 100,000 = 1 gauss). The Earth's magnetic field intensity is roughly between 25,000 - 65,000 nT (.25 - .65 gauss). Magnetic declination is the angle between magnetic north and true north. D is considered positive when the angle measured is east of true north and negative when west.  The magnetic inclination is the angle between the horizontal plane and the total field vector, measured positive into Earth. In older literature, the term “magnetic elements” is often referred to as D, I, and H.

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