1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
emmainna [20.7K]
1 year ago
11

Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support

(the atlanto-occipital joint). The muscles in the back of the neck musttherefore exert a force to keep it erect. That is why your head falls forward when you fall asleep in class. If the perpendicular distance between the line of action for the weight of the head and thepivot point is rw = 2.4 cm and the perpendicular distance between the line of action for theforce the muscles exert on the head and the pivot point is rMi=5.1 cm. determine each or thefollowina. (Assume the weight of the head is 50 N.)

Physics
1 answer:
alexandr1967 [171]1 year ago
8 0

We are asked to determine the force required by the neck muscle in order to keep the head in equilibrium. To do that we will add the torques produced by the muscle force and the weight of the head. We will use torque in the clockwise direction to be negative, therefore, we have:

\Sigma T=r_{M\perp}(F_M)-r_{W\perp}(W)

Since we want to determine the forces when the system is at equilibrium this means that the total sum of torque is zero:

r_{M\perp}(F_M)-r_{W\perp}(W)=0

Now, we solve for the force of the muscle. First, we add the torque of the weight to both sides:

r_{M\perp}(F_M)=r_{W\perp}(W)

Now, we divide by the distance of the muscle:

(F_M)=\frac{r_{W\perp}(W)}{r_{M\perp}}

Now, we substitute the values:

F_M=\frac{(2.4cm)(50N)}{5.1cm}

Now, we solve the operations:

F_M=23.53N

Therefore, the force exerted by the muscles is 23.53 Newtons.

Part B. To determine the force on the pivot we will add the forces we add the vertical forces:

\Sigma F_v=F_j-F_M-W

Since there is no vertical movement the sum of vertical forces is zero:

F_j-F_M-W=0

Now, we add the force of the muscle and the weight to both sides to solve for the force on the pivot:

F_j=F_M+W

Now, we plug in the values:

F_j=23.53N+50N

Solving the operations:

F_j=73.53N

Therefore, the force is 73.53 Newtons.

You might be interested in
Without using a micrometer screw gauge, how do I find the average diameter of a long piece of thin wire using a metre rule and a
Mice21 [21]

Answer:

Wind the long piece of thin wire around the uniform glass rod multiple times, find the length of the total diameters using the metre ruler, and divide by the number of times you wound it around the rod.

Explanation:

Since the diameter of one long piece of thin wire is too thin to be measured by a metre ruler, you can wind it multiple times and push it side by side to get a length you can measure.

For example, if you wound it around 20 times and the total length of 20 diameters of the wire side-by-side is 2.0 cm, one winding, which is the diameter would be 2.0cm ÷ 20 = 0.10cm or 1mm.

5 0
2 years ago
How do you put 1/2000 into scientific notation? *
maksim [4K]
It’s e 2.0 x 10^-4 because it is a fraction
4 0
3 years ago
How do icebergs form
pishuonlain [190]

Answer:

They break off large ice sheets found at the North and South poles.

5 0
2 years ago
Can you hear it? In the cartoon space rocket, why do you think you would not be able to hear the whoosh of the rocket engine in
Brums [2.3K]

Answer:

Because space is a void with no air flow

Explanation:

7 0
3 years ago
A 0.140-kg baseball is dropped from rest. It has a speed of 1.20 m/s just before it hits the ground, and it rebounds with an upw
irga5000 [103]

Answer:

22 N upward

Explanation:

From the question,

Applying newton's second law of motion

F = m(v-u)/t....................... Equation 1

Where F = Average force exerted by the ground on the ball, m = mass of the baseball, v = final velocity, u = initial velocity, t = time of contact

Note: Let upward be negative and downward be positive

Given: m = 0.14 kg, v = -1.00 m/s, u = 1.2 m/s, t = 0.014 s

Substitute into equation 1

F = 0.14(-1-1.2)/0.014

F = 0.14(-2.2)/0.014

F = 10(-2.2)

F = -22 N

Note the negative sign shows that the force act upward

6 0
3 years ago
Other questions:
  • As you (increase, decrease) in altitude, air pressure decreases.
    10·1 answer
  • a paraellel plate capacitor consists of 2 large circular sheets of metal separated by 1.53 cm. The electric field energy density
    9·1 answer
  • The Milky Way is our Galax. Where are we located in Milky Way?​
    15·1 answer
  • Particle of the nucleus that has no electrical charge
    12·2 answers
  • How many planets are in our solar system
    13·2 answers
  • The mass of an object is independent of its location.
    5·1 answer
  • HELP PLS ASAP<br><br> what is a scientific law? pls dont copy and paste. pls put in ur own words.
    7·2 answers
  • The _______ of a sound wave is defined as the amount of energy passing through a unit area of the wave front in a unit of time.
    15·1 answer
  • Some people today claim the Earth is flat. Produce an argument to prove that the
    8·2 answers
  • Please help, and give an explanation on what you did. Thanks a lot :]​
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!