Answer:
a) a= 19 m/s2, b ) F = F = 38 N
c) the correct one is B
Explanation:
1) To solve this exercise, let's use the concept of torque, let's start by looking for the mass of the mass of the head, which is 65 of 65 kg
m= 0.06 65 = 3.9 kg
torque is defined
τ = F x R
the bold indicate vectors
τ = F R sin θ
the force is the weight of the head and the distance R = 0.20 m
τ = mg R sin θ
τ = 3.9 9.8 0.2 sin 50
τ = 5.86 N m
Newton's second law expression for rotational motion is
τ = I α
In general, the head is approximated by a sphere, so the moment of foolishness with respect to the base of the neck (turning point) using the parallel axis theorem is
I = I_sphere + m d²
Neck height data is not indicated, so we will assume that it is zero (d = 0)
I = 2/5 m R²
angular and linear acceleration are related
a = α R
α = a / R
let's replace
τ = 2/5 mR² (a / R)
a = 5/2 τ / mR
let's calculate
a = 5/2 5.86 / (3.9 0.2)
a = 18.8 m / s²
a= 19 m/s²
2) as the neck and the head are related, the forces are action and reaction, therefore the neck force is
F = m g
F = 3.9 9.8 = 38.2 N
F = 38 N
3) He asks us about the efficiency of the headrest, after reviewing the different alternatives, the correct one is B
Yes. A headrest ensures that both the head and the body experience the same forward force at approximately the same time.
A vector is 9.55m long and points in a -48.0 degree direction. find the x component
Answer:
x=6.39 m
Explanation:
Rectangular Components of a Vector
Vectors can be expressed in several forms, including the magnitude-angle form, and the rectangular-coordinates form.
If the magnitude r and angle β are given, we can find the rectangular coordinates (x,y) as follows:
[tex]x=r\cos\beta[/tex]
[tex]y=r\sin\beta[/tex]
The vector of the question has a magnitude of r=9.55 m and an angle β=-48°. The x-component is:
[tex]x=9.55\cdot\cos(-48^\circ)[/tex]
Using a digital calculator:
x=6.39 m
An underwater sound source emits waves of frequency 30 kHz in all directions. How does the intensity of the waves (in Watts/m2) vary with distance r from the source?
a) 1/r^3
b) 1/r^2
c) 1/r
d) None of above
When an underwater sound source emits waves of frequency 30 kHz in all directions, the intensity of the waves (in Watts/m2) vary with distance r from the source by the relation 1/r²
As the intensity mechanical sound wave is inversely proportional to the square of the distance from the source, therefore the correct option is B.
What is the Wavelength?Wavelength can be understood in terms of the distance between any two similar successive points across any wave for example wavelength can be calculated by measuring the distance between any two successive crests.
It is the total length of the wave for which it completes one cycle.
The intensity of a mechanical wave is inversely proportional to the square of the distance from the source.
An underwater sound source emits waves of frequency of 30 kHz in all directions, the intensity of the waves (in Watts/m2) varies with distance r from the source by the relation 1/r², therefore the correct option is B.
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show answer No Attempt 50% Part (b) Calculate the non-relativistic speed of these electrons v in m/s.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value is [tex]v = 9.18 *10^{6} \ m/s[/tex]
Explanation:
From question we are told that
The potential difference is [tex]\Delta V = 0.24 kV = 0.24 *10^{3} \ V[/tex]
Generally the the non-relativistic speed of these electrons is mathematically represented as
[tex]v = \sqrt{\frac{2 * e * \Delta V}{m} }[/tex]
Here m is the mass of an electron with value [tex]m = 9.11 *10^{-31 } \ kg[/tex]
e is the charge on an electron with value [tex]e = 1.60 *10^{-19} \ C[/tex]
So
[tex]v = \sqrt{\frac{2 * 1.60 *10^{-19} * 0.24 *10^{3} }{9.11*10^{-31}} }[/tex]
=> [tex]v = 9.18 *10^{6} \ m/s[/tex]
2. Which of the following is a true statement.
Sound travels faster than light.
Sound travels slower than light
Answer:
Sound travels slower than light
Explanation:
Sound travels at around 1/3 km per second, while light travels around 300,000 km per second.
Also, this is the reason you see the lightning before you hear the thunder.
I hope this helped.
Answer:
Sound travels slower than light
Explanation:
Bc light is faster than sound
The most interpersonal constructive passion response to relational conflict is..
Answer:
loyalty
Explanation:
If an object has zero acceleration, does it have to have zero velocity?
Answer:
Yes, the velocity would also be zero.
Explanation:
Acceleration is the change in velocity over time, therefore, there has to be a change in velocity for something to accelerate. which means without acceleration, the object has no velocity.
A baseball's resultant velocity is 25.79 m/s, at 68.64° from the level ground.
Determine the vertical component of the baseball's velocity.
Answer:
Vy = 24.01 [m/s]
Explanation:
To solve this problem we must understand that velocity is a vector and therefore has magnitude and direction, in this way we can decompose the velocity in the components x & y, by means of the trigonometric functions of the sine and cosine of the angle.
For the vertical component, the sine of the angle is used.
Vy = 25.79*sin(68.64)
Vy = 24.01 [m/s]
the state of matter that has low thermal expansion
Answer:
Matter
Explanation:
Because it is solid
Answer:
Solid
Solid < Liquid < Gas
A person has a mass of 1000 g and an acceleration of 20 M/S/S what is the force on the person
Answer:
The answer is 20 NExplanation:
The force acting on an object can be found by using the formula
force = mass × accelerationFrom the question
mass = 1000 g = 1 kg
acceleration = 20 m/s²
We have
force = 20 × 1
We have the final answer as
20 NHope this helps you
2.9030 cm has 4 significant digits.
TRUE OR FALSE
Answer: false
Explanation:
Sand is made of tiny pieces of rock that have been worn
down by wind and water. Explain why the formation of
sand is a physical change.
Answer:
Sand is a form of physical change because it shows how one object is being worn out (broken down) into another object by nature.
Explanation:
three charges are located at 100m intervals along a horizontal line: a charge of -3.0C on the left, 2.0C in the middle, and 1.0C on the right. What is the resultant force on the 1.0C charge due to the other two
We know, force is given by :
[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]
Here, k in a constant.
[tex]Net \ Force = F_1+F_2\\\\Net \ Force = k(\dfrac{Qq_1}{r_1^2}+\dfrac{Qq_2}{r_2^2})\\\\Net \ Force = k( \dfrac{-3}{50}+\dfrac{2}{50})\\\\Net \ Force = 9\times 10^9\times \dfrac{-1}{50}\ N\\\\Net\ Force = -1.8\times 10^8\ N[/tex]
Hence, this is the required solution.
rt A How much work does the electric motor of a Van de Graaff generator do to lift a positive ion (q=e) if the potential of the spherical electrode is 2.0 MV ?
Answer:
W = 2.0 MeV = 3.2*10⁻¹³ J
Explanation:
Assuming that the ion is located originally at a point where the electrostatic potential is zero, the change in energy of the ion is just the change in electrostatic potential times the charge of the ion, as follows:[tex]\Delta E = e*V = 1.6e-19 C * 2.0e6 V = 2.0 MeV = 3.2e-13 J[/tex]
This change in energy, assuming no friction present, must be equal to the work done by the motor on the ion:W = 2.0 MeV = 3.2*10⁻¹³ J.
Which of the following does not discribe a mineral
Answer:
give us some further context to answer your question as well
Explanation:
is newton's first law true on earth?
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.
THIS LAW IS TRUE AS IT ALSO HAVE A REAL LIFE EXAMPLE.
Examples of Newton's 1st Law : If you slide a hockey puck on ice, eventually it will stop, because of friction on the ice. It will also stop if it hits something, like a player's stick or a goalpost.
1) Construct a graph showing the relationship between and independent variable and a dependent variable. 2) Demonstrate potential and kinetic energy. 3) Design a pendulum. 4) Investigate which variables influence the period of a pendulum. 5) Solve a problem using the scientific method. 6) Use graphs to characterize gow drop height responds to bounce height. (Next answer questions 1 - 6). 1) Write the goal of the lab or the question you tried to answer? 2) which observations, experiences, or lesson materials helped you form a hypothesis? 3) State your hypothesis? 4) Use the data from your experiment to complete these data tables? [Data Table 1: Period vs. Mass] Mass(g) / Time for 10 periods (s). [ Data Table 2: Period vs. String Length] String Length (cm) / Time for 10 periods (s). ( Question 5) Graph your data: A) Determine the values in seconds (s) for the y-axis based on your time data. B) Plot mass vs. time for 10 periods on the first graph. C) Plot string length vs. time for 10 periods on the second graph. ( question 6) Compare your data with your hypothesis. Explain how the data supports or does not support your hypothesis. If your data does not support your hypothesis, use the data you collected to answer the original question. { Truly Need Help and will mark brainlest} Please Please be very honest with your response.
According to the kinetic theory, what happens when the temperature of water
increases?
The water molecules increase their speed.
The water molecules do not change speed.
The water molecules decrease their speed
PLEASE HELP
A train is traveling at a speed of 50km/hr. How.many hours will it take the train to travel 800 km?
Answer:
It would take 16 hours
Explanation:
800 divided by 50 = 16
Brainly pls
Answer: [tex]t[/tex] = 16
Explanation:
Hey there! I will give the following reason, if you have any questions feel free to ask me in the comments below.
Because a train is traveling at a speed of 50 km/hr and a train needs to travel 800 km, you would need to divide the distance by the speed to find the hours.
Formula: [tex]t[/tex] = [tex]\frac{distance}{speed}[/tex]
The distance would be 800, and the speed would be 50.
[tex]t = \frac{800}{50}[/tex]
Simplify.
[tex]t = 16[/tex]
~I hope this helps you! :)~
Write the vectors labeled A, B and C with rectangular coordinates.
Focus on vector A. Start at the base of the vector which is at (1,1)
Then notice how we have to move 3 units to the right and 2 units up to get to the tip of the vector where the arrow is located. So this is at (4,3)
The fact that we moved 3 units to the right and 2 units up means that vector A is <3, 2>
So we'll type 3 in the first box and 2 in the second box.
======================================================
We use the same idea for vector B
Start at the base and move to the tip. Doing so has us move 1 unit left and 3 units down.
Vector B = <-1, -3>
We type -1 in the first box, and -3 in the second box.
======================================================
Finally onto vector C
Start at the base (0,0). To move to the tip, we need to go 3 units left and 3 units up
Vector C = <-3, 3>
-3 goes in the first box and 3 goes in the second box
======================================================
In general, vectors are useful to tell us a specific direction in which to go. They're useful in physics to determine how exactly a force is being applied, or how a particle is moving.
A speed skater moving across frictionless ice at 8.8 m/s hits a 6.0 m -wide patch of rough ice. She slows steadily, then continues on at 5.8 m/s . What is her acceleration on the rough ice?
Recall that
v² - u² = 2 a ∆x
where u and v are initial and final velocities, respectively; a is acceleration; and ∆x is the distance traveled (because the skater moves in only one direction).
So we have
(5.8 m/s)² - (8.8 m/s)² = 2 a (6.0 m)
a = ((5.8 m/s)² - (8.8 m/s)²) / (12 m)
a = -3.65 m/s²
How are gas giants similar to one another?
Answer:
they are all made of gass and they are all giants.
Explanation:
Answer:
How are the gas giants similar to one another? dont have solid surfaces and are much larger than earth. Why do all of the gas giants have thick atmospheres? Because they are so massive, the gas giants exert a much stronger gravitational force than the terrestrial planets
Explanation:
HELP!
Which process of heat transfer makes milk boil?
Answer:
milk is raised to a certain level for sometimes and immediately cooled to the lower degree
The two main types of weathering are (4 points)
A. mechanical and physical
B. physical and kinetic
C. chemical and physical
D. chemical and acidic
Answer:
b
Explanation:
Answer:
its acually c
Explanation:
a single frictionless roller coaster car of mass m=750 kg tops the first hill with speed v=15 m/s ar height h =40m as shown
1) Find the speed of the car at B and C
2) if mass m were doubled, would the speed at B increase, decrease, or remain the same?
1. The speed of the roller coaster car at point B and C: are 19.8 m/s and 0 m/s respectively.
2. If mass (m) of the roller coaster car were doubled, the speed at B would increase because energy is dependent on the mass of an object.
Given the following data:
Mass of roller coaster car = 750 kgSpeed of roller coaster car = 15 m/sHeight = 40 meters1. To find the speed of the roller coaster car at point B and C:
First of all, we would determine the potential energy of the roller coaster car by using the formula:
[tex]P.E = mgh[/tex]
Where:
m is the mass of object.g is the acceleration due to gravity ([tex]9.8\;m/s^2[/tex]).h is the height of an object.From the diagram, height at point B = [tex]\frac{h}{2} = \frac{40}{2} = 20[/tex] meters
[tex]P.E = 750(9.8)(20)[/tex]
P.E = 147000 Joules.
Next, we would determine the speed by applying the law of conservation of energy.
[tex]Kinetic\;energy = Potential\;energy\\\\\frac{1}{2} mv^2 = mgh[/tex]
Substituting the values, we have;
[tex]147000 = \frac{1}{2} (750)v^2\\\\147000 = 375v^2\\\\v^2 = \frac{147000}{375} \\\\v^2 = 392\\\\v = \sqrt{392}[/tex]
Speed, v = 19.8 m/s
From the diagram, at point C, the speed is equal to zero (0) meters per seconds.
2. If mass (m) of the roller coaster car were doubled, the speed at B would increase because energy is dependent on the mass of an object.
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If a wave is traveling at a constant speed, and the frequency increases, what would happen to the wavelength?
It would increase
It would decrease.
It would remain constant.
It would drop to zero.
If a wave is traveling at a constant speed, and the frequency increases, the wavelength would decrease.
What is wavelength?The wavelength is the distance between the adjacent crest or trough of the sinusoidal wave. The wavelength is the reciprocal of the frequency of the wave.
Wavelength λ = 1 / frequency
The wavelength and frequency are inversely related to each other. So, when frequency is increased, the wavelength increases.
Thus, the wavelength of would decrease if the frequency increases.
Learn more about wavelength.
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Answer:
B. It would decrease
Explanation:
Suppose Tom Harmon17 is standing at the exact center of the Ohio State football field18 on the 50 yard line. The field is 300 feet long and 160 feet wide. Suppose the ball leaves Harmon’s hand at a height of six feet and has initial velocity v(0) = 40i + 39j + 32k feet per second where j points toward the sideline, i points toward the end zone, and k = i × j points straight up. The acceleration due to gravity is −32k feet per second squared and the mass of the football is .45 kilograms.
(a) Determine a parameterization for the position of the football at time t seconds after it is thrown.
(b) Suppose David Nelson19 catches the ball when it is six feet above the ground. Is Nelson in bounds or out of bounds when he catches the ball? (Assume Nelson’s toes are touching the ground directly below the ball when he catches the ball.)'
Answer:
a) x = 40 t , y = 39 t , z = 6 + 32 t - 16 t ², b) x = 80 feet , y = 78 feet , the ball came into the field
Explanation:
a) This is a projectile launch exercise, where in the x and y axes there is no acceleration and in the z axis the acceleration of the acceleration of gravity, let's write the equations of motion in each axis
Since the cast is in the center of the field, let's place the coordinate system
x₀ = 0
y₀ = 0
z₀ = 6 feet
x-axis (towards end zone, GOAL zone)
x = xo + v₀ₓ t
x = 40 t
y-axis (field width)
y = y₀ + [tex]v_{oy}[/tex] t
y = 39 t
z axis (vertical)
z = z₀ + v_{oz} t - ½ g t²
z = 6 + 32 t - ½ 32 t²
z = 6 + 32 t - 16 t ²
b) The player catches the ball at the same height as it came out, so we can find the time it takes to arrive
z = 6
6 = 6 + 32 t - 16 t²
(t - 2)t = 0
t=0 s
t= 2 s
The ball position
x = 40 2
x = 80 feet
y = 39 2
y = 78 feet
the dimensions of the field from the coordinate system (center of the field) are
x_total = 150 feet
y _total = 80 feet
so we can see that the ball came into the field
The lungs are large organs which contain smaller, expandable sacs.
These sacs greatly increase the surface area of the lungs.
Why is a large surface area important to the function of the lungs? A. Large amounts of liquid wastes and fatty tissue must be stored in the lungs. B. Oxygen in air taken in by the lungs must move quickly through the lung tissue and into the blood. C. The lungs must be very sturdy and rigid so they cannot move. D. The lungs must be able to filter oxygen from water while the organism is swimming.
Answer:
B. It is B because without this much space for oxygen and blood to flow and go through, we would not survive.
Explanation:
Consider two current-carrying circular loops. Both are made from one strand of wire and both carry the same current, but one has twice the radius of the other. If the magnetic field strength at the center of the smaller loop is B, what is the magnetic field strength at the center of the larger loop
Explanation:
The magnetic field at the center of a current-carrying circular loop is given by :
[tex]B=\dfrac{\mu_o I}{2r}[/tex]
Where, I is current and r is radius of loop
We have, two current-carrying circular loops. Both are made from one strand of wire and both carry the same current, but one has twice the radius of the other.
For smaller loop, the magnetic field is B (with radius r)
For larger loop, let the magnetic field be B' (with radius r', r'=2r). So,
[tex]B'=\dfrac{\mu_o I}{2r'}\\\\B'=\dfrac{\mu_o I}{2(2r)}\\\\B'=\dfrac{1}{2}\times \dfrac{\mu_o I}{2r}\\\\B'=\dfrac{1}{2}B[/tex]
Hence, the magnetic field strength at the center of the larger loop is half of the magnetic field strength at the center of the smaller loop.
Will ice melt faster in salt, sugar or water?
Answer:
Water because the salt will just make it colder and the sugar won't do anything
8. A dog runs with an initial speed of 7.5 m/s on a waxed floor. It slides to a stop in 15 sec. What
is the acceleration?
(10 Points)
O-7.5 m/s
-0.5 m/s2
O -7.5 m/s2
7.5 mi/hr
Answer:
-0.5 m/s²
Explanation:
Step 1: Given data
Initial velocity of the dog (u): 7.5 m/sFinal velocity of the dog (v): 0 m/s (Stop)Time elapsed (t): 15 sStep 2: Calculate the acceleration of the dog
The acceleration (a) is equal to the change in the velocity over the time elapsed.
a = v - u / t
a = 0 m/s - 7.5 m/s / 15 s
a = -0.5 m/s²