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.
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 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]
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
A ball weighing 60 N is swinging like a pendulum at the end of a 6.0 m rope. As the ball swings through its lowest point, its speed is measured at 5.0 m/s. What is the tension in the rope at this point?
A. 58.6 N
B. 85.4 N
C. 90.2 N
D. 97.3 N
Answer:
B. 85.4 N
Explanation:
The tension in the rope at the lowest point of the motion of the ball is antiparallel to the weight of the ball. By Newton's laws we construct the following equation of equilibrium:
[tex]\Sigma F = T - W = \left(\frac{W}{g} \right)\cdot \frac{v^{2}}{L}[/tex] (1)
Where:
[tex]T[/tex] - Tension in the rope, measured in newtons.
[tex]W[/tex] - Weight, measured in newtons.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]v[/tex] - Speed of the ball, measured in meters per second.
[tex]L[/tex] - Length of the rope, measured in meters.
If we know that [tex]W = 60\,N[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]v = 5\,\frac{m}{s}[/tex] and [tex]L = 6\,m[/tex], then the tension in the rope at this point is:
[tex]T = W+\frac{W\cdot v^{2}}{g\cdot L}[/tex]
[tex]T = W\cdot \left(1+\frac{v^{2}}{g\cdot L} \right)[/tex]
[tex]T = (60\,N)\cdot \left[1+\frac{\left(5\,\frac{m}{s} \right)^{2}}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (6\,m)} \right][/tex]
[tex]T = 85.492\,N[/tex]
Hence, the correct answer is B.
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
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
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:
A fruit bat falls from the roof of a cave. We know that her potential energy was
600 J, and that the roof of the cave was 12.8 meters high. What is her velocity
when she hits the ground?
Answer:
v = 15.65 m/s
Explanation:
We use conservation of mechanical energy between initial (i) and final (f) states:
Pi + KEi = Pf + KEf
At the top of the cave at the instant the bat starts to fall, there is only potential energy since the bat's velocity is zero.
Pi = m g h = 600 J
and the KEi = 0 J (no velocity)
Knowing the height of the cave's roof (12.8 m) , we can find the mass of the bat:
m = 600 J / (g 12.5) = 4.9 kg
Using conservation of mechanical energy, the final state is:
Pf + KEf = 600 J
with Pf = 0 (just touching the ground)
KEf= 1/2 4.9 (v^2)
and we solve for the velocity:
600 J = 0 + 1/2 4.9 (v^2)
v^2 = 600 * 2 / 4.9 = 244.9
v = 15.65 m/s
Use the following information to answer questions 6 and 7:
A61.0 kg grocery cart is sitting at rest. In order to change the cart's state of motion, Xavier must apply 72.1
Newtons of force on the cart.
6. How much magnitude of force does the cart exert back on Xavier's hand?
A. 4400 N
B. 1.20 N
C. 72.1 N
D. 0.00 N
After 10 seconds, the dirt has achieved a velocity of +3.62 m/s. Xavier is still applying 72.1 Not force on the
cart.
7. Xavier's sister Maria claims that the cart is in dynamic equilibrium. Is Maria correct?
A Maria is correct because the cart is traveling at a constant velocity while experiencing balanced
forces.
B. Maria is correct because the cart's velocity has changed.
C. Maria is incorrect because the cart is traveling at a constant velocity while experiencing
unbalanced forces.
D. Maria is incorrect because the cart's velocity has changed
Question 6
C. 72.1 N
Its simply the newton Third law, whenever two objects interact, they exert equal and opposite forces on each other.
Question 7
D. Maria is incorrect because the cart's velocity has changed
The car is accelerating so, It is not in dynamic equilibrium. Remember that by the Newton Second Law:
F = ma
The cart is in dynamic equilibrium. The correct options for the two question are:
6. C
7. A
6.) Given that a 61.0 kg grocery cart is sitting at rest. And Xavier applied 72.1 Newtons of force on the cart.
According to Newton's third law of motion which state that, in every action, there will be equal and opposite reaction. The magnitude of force That the cart exert back on Xavier's hand will be opposite and equal to the force applied. which is negative 72.1 N
7.) If the grocery cart is moving in a constant velocity, then it will achieve a dynamic equilibrium. In this scenario, the air resistance force balances with the applied force.
Therefore, Maria is correct because the cart is traveling at a constant velocity while experiencing balanced forces.
Learn more about equilibrium of forces here: https://brainly.com/question/9076091
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 !
What is the slope of the line that passes through the points (-8, -3)(−8,−3) and (-12, -3) ?(−12,−3)? Write your answer in the simplest form.
single black dude
Notice that both of those points are 3 units below the x-axis. So the line is horizontal ... its slope is zero.
give an example of a normal force. type below.
Normal force is the force exerted when an object is on an surface. So an example could be a pile of books on top of a table.
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.
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.
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
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
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:
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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.
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.
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:
Question 10 of 10
In the photoelectric effect, an electric current forms when light strikes a metal
surface. Which statement explains what causes the current?
O A. Electrons flow from one atom to another because the light acts as
a wave.
O B. The light causes electrons to flow in different directions within an
atom because light acts as a wave.
O C. Electrons are destroyed when light strikes a surface because the
light acts as particles.
D. Electrons are knocked off the surface when light strikes it because
the light acts as particles.
Explanation:
D. I hope i helped it should be right but if it isn't my bad
In the photoelectric effect, an electric current forms when light strikes a metal surface because electrons are knocked off the surface when light strikes it because the light acts as particles, The correct option is D.
What is the photoelectric effect?
It is the process of emission of electrons from the material because of absorption of electromagnetic radiation in form of photons of light waves.
The photoelectric effect explains the particle behavior of the light waves.
The photoelectric effect is responsible when electrons are knocked off the surface when light strikes it because the light acts as particles.
Learn more about the photoelectric effect
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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 60-W light bulb radiates electromagnetic waves uniformly in all directions. At a distance of 1.0 mfrom the bulb, the light intensity is I0, the average energy density of the waves is u0, and the rms electric and magnetic field values are E0 and B0, respectively.
At 2.0 m from the bulb, what is the light intensity?
Answer:
I0/4
Explanation:
If the difference is increasedby a factor of two(i.e twice it's original value), then the light intensity happens to get reduced by one-fourth. This means that the light intensity would be:
I0/4
.
Calculate the potential energy of a 6 kg bowling ball suspended 3 m above the surface of the Earth.
Answer: 176.4 J
Explanation:
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
if u want to play among us have fun the code is UQEZFF
Answer:
ight bet
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
How does solar energy impact the environment? Use in your own words.
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: