Answer:
False
Explanation:
We still use the old way. It's easier to understand the old way, and its NOT outdated.
Assume that, when we walk, in addition to a fluctuating vertical force, we exert a periodic lateral force of amplitude 25 NN at a frequency of about 1 HzHz. Given that the mass of the bridge is about 2000 kgkg per linear meter, how many people were walking along the 144-mm-long central span of the bridge at one time, when an oscillation amplitude of 75 mmmm was observed in that section of the bridge
Complete Question
The complete question is shown on the first uploaded image
Answer:
Explanation:
From the question we are told
The amplitude of the lateral force is [tex]F = 25 \ N[/tex]
The frequency is [tex]f = 1 \ Hz[/tex]
The mass of the bridge per unit length is [tex]\mu = 2000 \ kg /m[/tex]
The length of the central span is [tex]d = 144 m[/tex]
The oscillation amplitude of the section considered at the time considered is [tex]A = 75 \ mm = 0.075 \ m[/tex]
The time taken for the undriven oscillation to decay to [tex]\frac{1}{e}[/tex] of its original value is t = 6T
Generally the mass of the section considered is mathematically represented as
[tex]m = \mu * d[/tex]
=> [tex]m = 2000 * 144[/tex]
=> [tex]m = 288000 \ kg[/tex]
Generally the oscillation amplitude of the section after a time period t is mathematically represented as
[tex]A(t) = A_o e^{-\frac{bt}{2m} }[/tex]
Here b is the damping constant and the [tex]A_o[/tex] is the amplitude of the section when it was undriven
So from the question
[tex]\frac{A_o}{e} = A_o e^{-\frac{b6T}{2m} }[/tex]
=> [tex]\frac{1}{e} =e^{-\frac{b6T}{2m} }[/tex]
=> [tex]e^{-1} =e^{-\frac{b6T}{2m} }[/tex]
=> [tex]-\frac{3T b}{m} = -1[/tex]
=> [tex]b = \frac{m}{3T}[/tex]
Generally the amplitude of the section considered is mathematically represented as
[tex]A = \frac{n * F }{ b * 2 \pi }[/tex]
=> [tex]A = \frac{n * F }{ \frac{m}{3T} * 2 \pi }[/tex]
=> [tex]n = A * \frac{m}{3} * \frac{2\pi}{25}[/tex]
=> [tex]n = 0.075 * \frac{288000}{3} * \frac{2* 3.142 }{25}[/tex]
=> [tex]n = 1810 \ people[/tex]
A solid ball is rolling along a horizontal surface at 3.7 m/s when it encounters an upward
incline. If it rolls without slipping up the incline, what maximum height will it reach?
Answer:
h = 0.697 [m]
Explanation:
To solve this problem we must use the energy conservation theorem, where it tells us that kinetic energy is converted to potential energy or vice versa.
[tex]E_{kinet}=E_{pot}[/tex]
where:
Ekinet = kinetic energy [J]
Epot = potential energy [J]
[tex]\frac{1}{2}*m*v^{2}=m*g*h\\0.5*(3.7)^{2} =9.81*h\\h =(6.845)/9.81\\h = 0.697 [m][/tex]
give 2 reasons why a person should move away from "isolating muscles"
Answer:
1) - They should move away because its cold
2) - You can get hypothermia......
Explanation:
Obesity and stress are confirmed risk factors for which of the following?
lost of nutrition in human
Answer:
True
Explanation:
Obesity and stress are confirmed risk factors for CHD
a book falls off a 1-meter tall table. how long will it take for the book to hit the floor ?
Answer:
0.45 s
Explanation:
Step 1: Given and required data
Displacement of the book (s): 1 mInitial velocity of the book (u): 0 m/s (rest)Acceleration due to the gravitational force of Earth (a): 9.8 m/s²Step 2: Calculate the time that it will take for the book to hit the floor (t)
The book undergoes a Uniformly Accelerated Motion. We can calculate the time required to reach the floor using the following suvat equation.
s = u × t + 1/2 × a × t²
s = 0 m/s × t + 1/2 × a × t²
s = 1/2 × a × t²
t = √(2s/a)
t = √(2 × 1 m/9.8 m/s²)
t = 0.45 s
10. A 90 kg box is sliding across a surface at a constant velocity while experiencing a rightward applied
force of 40 N. Calculate the force of friction acting on the box.
A. -40N
B. +40N
C.-2.5 N
D. 0 N
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
fr = -40 N
In the formulas for latent heat of fusion and latent heat of vaporization, what does Q represent?
Answer:
Q is the amount of energy released or absorbed during the change of phase of the substance (in kJ or in BTU), m is the mass of the substance (in kg or in lb), and. L is the specific latent heat for a particular substance (kJ kg−1 or in BTU lb−1), either Lf for fusion, or Lv for vaporization.
I hope this helps∪ω∪
Answer:
A
Explanation:
HELP ASAP!! i’ll mark you the brainliest!!
Answer:
yes
Explanation:
Which has a greater force: a semi-truck at rest or a moving bicycle?
Although the semi truck certainly has a larger mass, it is not in motion and therefore does not have any momentum. The bicycle however has both mass and velocity and therefore has the larger momentum of the pair.
Numerical Problems
A bus covers a distance of 600 metres in 30 seconds. Calculate the speed of
the bus.
Answer:
20 m/s.
Explanation:
From the question given above, the following data were obtained:
Distance travelled = 600 m
Time taken = 30 s
Speed =?
Speed can be defined as the distance travelled per unit time. Mathematically, it is expressed as:
Speed = Distance /time
With the above formula, we can easily calculate the speed of the bus as follow:
Distance travelled = 600 m
Time taken = 30 s
Speed =?
Speed = Distance /time
Speed = 600 / 30
Speed = 20 m/s
Therefore, the speed of the bus is 20 m/s.
Just do the attachment
Answer: your answer is B I know that's what you picked but I believe it is correct! look below...
Explanation: A solution is made when one substance called the solute "dissolves" into another substance called the solvent. Dissolving is when the solute breaks up from a larger crystal of molecules into much smaller groups or individual molecules.
In order to form a solution, the solute must be surrounded, or solvated, by the solvent. Solutes successfully dissolve into solvents when solute-solvent bonds are stronger than either solute-solute bonds or solvent-solvent bonds.
BRAINLIEST?
A little girl is walking, swinging her arms through a 20° angle every 0.25 s. The length of each arm is 30 cm. Assuming that the arms move with constant speed during each swing, find the force that the blood vessel in her arm would exert on a 1-gram drop of blood from the end of the arm if her arm were not swinging.
Answer:
The force will be "[tex]9.8\times 10^{-3} \ N[/tex]".
Explanation:
The given values are:
Mass,
m = 1 gram
Angle,
Ф = 20°
As we know,
⇒ [tex]F=mg[/tex]
On substituting the given values in the above expression, we get
⇒ [tex]=(1.0\times 10^{-3})(9.8)[/tex]
⇒ [tex]=9.8\times 10^{-3} \ N[/tex]
What effect does atmospheric pressure have on density?
Answer:sometimes it commits to how it will happen
Explanation:
Answer:
Atmospheric pressure increases density
Explanation:
Atmospheric pressure decreases the volume of space, since volume is inversely proportional to density, density will increase.
what type of friction present when you wrench on a car?
Answer:Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why most forms of ground transportation use wheels, including bicycles, cars, 4-wheelers, roller skates, scooters, and skateboards.
Explanation:
An object whose specific gravity is 0.850 is placed in water. What fraction of the object is below the surface of the water?
Answer:
The fraction of the object that is below the surface of the water is ¹⁷/₂₀
Explanation:
Given;
specific gravity of the object, γ = 0.850
Specific gravity is given as;
[tex]specific \ gravity = \frac{density \ of the \ object}{density \ of \ water}\\\\0.85= \frac{density \ of the \ object}{1000 \ kg/m^3} \\\\density \ of the \ object = 850 \ kg/m^3[/tex]
Fraction of the object's weight below the surface of water is calculated as;
[tex]= \frac{850}{1000} \ \times\ 100\%\\\\= 85 \% \\\\= \frac{17}{20}[/tex]
Therefore, the fraction of the object that is below the surface of the water is ¹⁷/₂₀
what is the current definition of intelligence?
Answer:
the ability to learn, emotional knowledge, creativity, and adaptation to meet the demands of the environment effectively
A person pushing a bin with 45 N of force slides the 3 kg plastic bin on a rough surface with friction. The plastic bin is moving with a constant velocity. What is the net force acting on the box?
Answer:
F = 0
Explanation:
Given that,
Force acting to push a bin = 45 N
Mass of the plastic bin, m = 3 kg
The plastic bin is moving with a constant velocity.
We need to find the net force acting on the box. Constant velocity means the change in velocity is equal to 0. It means acceleration will be 0.
As a result, the force acting on the box is equal to 0.
Which of the following is true for valence electrons?
Valence electrons are always located in the outer most energy level.
Valence electrons are found only in radioactive isotopes.
Valence electrons are always located in the innermost energy level
Valence electrons are found only in negatively charged ions.
Answer:
Valence electrons are always located in the outer most energy level.
Explanation:
Valence electrons are the ones that are involved in chemical bonds. In order to take part in a chemical bonding, the outermost/valence electron needs to be involved. Thus, the answer is Valence electrons are always located in the outer most energy level.
If two ___ forces are applied to an object in opposite directions, the object does not move, or moves at a ___ , this means the forces are ___. If to ___ forces are applied to an object in opposite directions, the object does move, this means the forces are ___.
Answer:
Equal and opposite
Constant speed
Balanced
Unequal and non-opposite
Unbalanced
Explanation:
Balanced forces can be defined as forces which are equal in size but opposite in direction.
Now, these forces do not cause a change in motion because when they act on an object at rest, such an object will not move. For example, when attempt to push against a wall, the wall will push back with an equal but opposite force and neither you nor the wall will move.
While unbalanced forces are those that cause a change in the motion of an object.
Thus, these forces are said not to be equal and opposite.
giving brainiest to correct answer.
Imagine a 0.2 kg ball moving at 5 m/s colliding with a 0.3 kg ball moving at 2 m/s in the same direction. After the collision the 0.2 kg green ball stops moving and the 0.3 kg purple ball continues moving in the same direction.
giving brainiest to correct answer.
Answer:
[tex]5.33\ m/s[/tex]
Explanation:
[tex]We\ know\ that,\\Momentum=Mass*Velocity\\p=mv\\Hence,\\Lets\ first\ consider\ the\ case\ of\ the\ two\ balls\ 'Before\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Initial\ Velocity\ of\ the\ green\ ball=5\ m/s\\Initial\ Momentum\ of\ the\ green\ ball=5*0.2=1\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Initial\ Velocity\ of\ the\ pink\ ball=2\ m/s\\Initial\ Momentum\ of\ the\ pink\ ball=0.3*2=0.6\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'Before\ Collision'=1+0.6=1.6\ kg\ m/s[/tex]
[tex]Hence,\\Lets\ now\ consider\ the\ case\ of\ the\ two\ balls\ 'After\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Final\ Velocity\ of\ the\ green\ ball=0\ m/s\\Final\ Momentum\ of\ the\ green\ ball=0\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Final\ Velocity\ of\ the\ pink\ ball=v\ m/s\\Final\ Momentum\ of\ the\ pink\ ball=0.3*v=0.3v\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'After\ Collision'=0+0.3v=0.3v\ kg\ m/s[/tex]
[tex]As\ we\ know\ that,\\Through\ the\ law\ of\ conservation\ of\ momentum,\\In\ an\ isolated\ system:\\Total\ Momentum\ Before\ Collision=Total\ Momentum\ After\ Collision\\Hence,\\1.6=0.3v\\v=\frac{1.6}{0.3}=5.33\ m/s[/tex]
The weight of the bricks is 5000N. Calculate the mass of the bricks.
(1 kg weighs 10N)
Answer:
500kg
Explanation:
....................
Answer:
500Kg
Explanation:
1 kg = 10N
? =5000N
5000N÷10N * 1Kg = 500Kg
an unladen swallow flies 5 m/s how far has the bird traveled after 1 minute?
Answer: 300m
1 minute = 60s
the unladen swallow can fly: 60.5 = 300 (m)
Explanation:
A block that slides on a rough surface slows down and eventually stops. The reverse process never occurs. That is, a block at rest never begins to move and accelerate on a rough surface without the action of an external agent. The second situation is forbidden because it would violate:_________.
a) conservation of total energy
b) conservation of momentum
c) the first law of thermodynamics
d) the second law of thermodynamics
e) both the first and second law of thermodynamics
Gracias.
Answer:
d) the second law of thermodynamics
Explanation:
Here we take an example
The entropy represents a measurement of the energy dispersal in the system. Also, the campfire would an entropy example. The burning of the solid wood and then it became the ash, smoke and gases this all would be spread the energy to the outward as compared to the solid fuel
Therefore as per the given statement, the correct option is d.
Use the following information to answer questions 4 and 5:
A rock is launched vertically into the air at a velocity of 14.75 m/s.
4. Toby claims that the rock must come to rest before it can fall back towards the ground. Is Toby
correct?
A. Toby is correct because the rock is experiencing a negative acceleration, causing its negative
velocity to increase until the rock reaches a velocity of O m/s before becoming positive.
B. Toby is correct because the rock is experiencing a negative acceleration, causing its positive
velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.
C. Toby is incorrect because the rock is experiencing a positive acceleration, causing its positive
velocity to increase in magnitude.
D. Toby is incorrect because the rock is experiencing a negative acceleration, causing its positive
velocity to increase in magnitude.
5. Calculate the time it takes for the rock to reach its maximum height.
A. 1.50 seconds
B. 2.47 seconds
C. 3.00 seconds
D. 4.94 seconds
Question 4
B. Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.
Question 5
At the maximum height, velocity is 0, so:
v = v₀ - gt
0 = 14.75 - 9.8t
t = 14.75/9.8
t = 1.5 s (OPTION A)
4). In the given situation, the assertion that could be made regarding Toby would be:
B). Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.
5). The time that would be taken by the rock to attain its greatest height would be:
1.5 second
4). Tobby correctly states as rock would be undergoing a -ve acceleration which leads its +ve velocity to fall by the time rock attains the velocity of 0 m/s.
Thus, option B is the correct answer.
5). Given that,
Initial velocity([tex]v_{0}[/tex]) = 14.75 m/s
As we know,
Velocity remains 0 m/s at the greatest height,
So,
Velocity(v) [tex]= v_{0} - gt[/tex]
where
[tex]0 = 14.75 - 9.8t[/tex]
⇒ [tex]t = 14.75/9.8[/tex]
∵ [tex]t = 1.5 s[/tex]
Learn more about "Velocity" here:
brainly.com/question/18084516
Mark all the units for speed
Answer:
Speed. I am speed.
Explanation:
The FitnessGram Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. A single lap should be completed each time you hear this sound. Remember to run in a straight line, and run as long as possible.
A student heated 50mL of water from zero degree Celsius to 60 degree Celsius. How much energy did she use to heat the water? Remember cal = m x delta T
Answer:
Q = 12.5 kJ
Explanation:
Given that,
Mass of water, m = 50 mL = 0.05 kg
The temperature changes from 0 degree Celsius to 60 degree Celsius.
We need to find how much energy she use to heat the water. The energy required to heat the water is given by :
[tex]Q=mc\Delta T[/tex]
Where c is specific heat of water, c = 4186 J/kgºC
[tex]Q=0.05\times 4186 \times (60-0)\\\\=12558\ J[/tex]
or
Q = 12.5 kJ
So, the energy used to heat th water is 12.5 kJ.
a steel girder weighting 700 lb is hoisted from gund level to the roof of a 70-ft building using a chain that weighs 4lb/running foot. Find the work done
Answer:
66.475kJ
Explanation:
Work done is the product of the force and perpendicular distance in direction of the force.
Work done = Force × distance
Given
Weight = 700lb
Distance = 70ft
1lb force = 4.448N
700lb force = 700(4.448) = 3113.6N
Distance = 70(0.305) = 21.35m
Work done = 3113.6×21.35
Work done ≈ 66,475Joules
Work done = 66.475kJ
A spring with a mass attached to it is stretched from the rest position of 20 cm to the position of 87 cm. If the spring constant of this spring is 1729 N/m, what is the potential energy stored in this spring?
561.29 J
120.97 J
388.07 J
254.79 J
Answer:
388.07 J
Explanation:
Answer:
C) 388.07
Explanation:
It is a spring therefore, there must be Elastic potential energy. Now what is the formula for elastic potential energy? It is 1/2 *k *x^2
K=spring constant
x= displacement
1/2=.5 (hate fractions)
Now, Displacement simply means (how much was it moved?) So, that means subtract.
87-20= 67 x=67
Next, do x^2 (so you don't make a mistake by squaring everything :) )
67*67=4,489
NOW, do....
.5*1729*4,489=3,880,740.5
Now convert to Joules, I just did 3,880,740.5 / 10^3 = 3880.745
round to 3880.7 J
~There you go loves !
Look at this model of an atom. Where are the electrons located and how many are there?
Answer:
The electrons are on the outer shell, there are 10 of them.
Explanation:
There are two in the inner shell and eight in the outer shell, giving us a total of 10 electrons
Which statement accurately describes thermal energy?
Answer:
here are the options.
Answer:
the energy that is associated with temperature or D
Explanation:
Hope this helps