Answer:
a. Thus, the tension in the cord causes no change in angular momentum.
b. 0.112 N
c. -0.048 J
Explanation:
a) Explain if the tension force causes the change of angular momentum.
A centripetal force F initially acts on the block to keep at at a radius of 0.5 m and speed of 0.9 m/s.
When the cord is pulled, the tension causes a change in the centripetal force to a new value at a radius of 0.23 m.
But since the force is applied in the radial direction and not perpendicular to the radius, there is no torque applied (since torque τ = rFsinθ and θ = 0 thus τ = rFsin0 = 0)and thus, there is tangential acceleration α (since α = τ/I where I = rotational inertia of block)and thus no change in angular speed ω (since α = Δω/Δt, α = 0 ⇒ Δω/Δt ⇒ Δω = 0).
Since there is a no change in angular speed, there is thus no change in angular momentum.
Thus, the tension in the cord causes no change in angular momentum.
b) What is the tension in the cord in the final situation when the block moving in a circle with smaller radius.
The centripetal force in the cord is equal to the tension at the smaller radius.
We find the angular speed of the block from v = rω where v = initial tangential speed of block at r = 0.5 m = 0.9 m/s and r = 0.5 m.
So, ω = v/r = 0.9 m/s ÷ 0.5 m = 1.8 rad/s
The centripetal force at radius r = 0.23 m is F = mrω² where m = mass of block = 0.150 kg, r = distance = 0.23 m and ω = angular speed = 1.8 rad/s
So, F = 0.150 kg × 0.23 m × (1.8 rad/s)²
F = 0.150 kg × 0.23 m × 3.24 rad²/s²
F = 0.11178 kgmrad²/s²
F ≅ 0.112 N
c) How much work was done by the person who pulled on the cord
From work-kinetic energy principles, the work done by the tension equals the kinetic energy change of the block.
ΔK = W
1/2m(v₂² - v₁²) = W where m = mass of block = 0.150 kg, v₁ = initial speed of block = 0.9 m/s, v₂ = final speed of block distance r = 0.23 m,
Since the tangential speed v ∝ r the radial distance,
v₂/v₁ = r₂/r₁
v₂ = (r₂/r₁)v₁
= 0.23 m × 0.9 m/s ÷ 0.5m
= 0.207 m²/s ÷ 0.5 m
= 0.414 m/s
So, W = 1/2m(v₂² - v₁²)
W = 1/2 × 0.150 kg((0.414 m/s)² - (0.9 m/s)²)
W = 1/2 × 0.150 kg((0.1714 m/s)² - (0.81 m/s)²)
W = 1/2 × 0.150 kg((-0.6386 m²/s²)
W = 1/2 × -0.09579 kgm²/s²)
W = -0.0479 kgm²/s²
W = -0.0479 J
W ≅ -0.048 J
Q. Diagram shows a sound wave as being displayed on an oscilloscope screen. Draw the waveform of another sound wave on the same diagram which has twice the pitch and is half as loud.
Answer:
i want points
Explanation:
Find the y-component of this vector: 22.3 m 77.1° Remember, angles are measured from the +x axis.
Answer:
-21.7m
Explanation:
To find the y-component of the vector, we need to find the vertical displacement from the point at the bottom of the vector to the x-axis (or its y-coordinate value).
To calculate this we can create a triangle with the vector as the hypotenuse, the y-axis as the second side and draw an imaginary line from the end of the vector directly horizontally across to the y-axis.
We can use the given angle to find the angle between the y-axis and the angle. Since the angle of a quadrant is 90 degrees, the angle within our triangle must be [tex]90-77.1=12.9[/tex] degrees.
From here, to find the length of the side on the y-axis we can use the trigonometric cos function.
[tex]cos \theta =\frac{adjacent side}{hypotenuse}[/tex]
Therefore [tex]cos 12.9=\frac{y-component}{22.3}[/tex] and [tex]ycomponent = 22.3cos12.9[/tex]
This gives us a value of 21.7 (3.s.f) for our y-component.
Finally, the y-component is also a vector so it also needs a direction. Therefore like its coordinate, its value will be -21.7m.
Identify work or a task that you’d like to make easier by using a device or tool. Here are a few possibilities: Easily pick up paperclips or pins that have fallen on the floor. Make a bed in less time. Move laundry from a basket into a washing machine without bending down. Sweep the floor without bending down. Rinse a collection of dishes at the same time. Efficiently pass salt and pepper shakers around a table. Rescue somebody from a high place. Choose a task from the list or, better yet, come up with your own. Explain how your tool or device will make the task easier. Note the simple machines that the tool or device will use.
The work or a task that I'd like to make easier by using a device or tool is sweeping the floor without bending down through the use of a vacuum cleaner.
What is a Device?This is referred to as a mechanical or electronic equipment which is made or adapted for a particular purpose and makes work easier and faster through technological advancement.
In the case of sweeping the floor without bending down, a vacuum cleaner is most appropriate as it uses an electric motor that spins a fan, thereby resulting in the sucking in of air and any small particles caught up in it thereby making it the correct device to be used.
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A flashlight bulb is connected to two dry cells with an equivalent voltage of 4.50 V. If the bulb draws a current of 12.0 mA (1000mA = 1A), its resistance is (2 points) a 540. Ohms b 375 Ohms c 266 Ohms d 2.66 Ohms e 145 Ohms
Answer:
b. 375 Ohms
Explanation:
Given the following data;
Voltage = 4.5 V
Current = 12 mA
To find the resistance;
Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.
Mathematically, Ohm's law is given by the formula;
[tex] V = IR[/tex]
Where;
V represents voltage measured in voltage. I represents current measured in amperes. R represents resistance measured in ohms.Conversion:
1000 mA = 1 A
12 mA = 12/1000 = 0.012 A
[tex] R = \frac {V}{I} [/tex]
Substituting into the formula, we have;
[tex] R = \frac {4.5}{0.012} [/tex]
Resistance, R = 375 ohms
A car drives up a straight hill at a constant speed of 50 kilometers per hour. A truck drives over the crest of the hill at a constant speed of 50 miles per hour. What is the net force on the car and on the truck
As a result, the net pressures on the automobile and truck are zero.
what is pressure ?
If you tried to smash a bowling pin into the wall, nothing would happen except that people would stop lending you bowling pins. If you used the same force to hammer a nail, the nail would be far more likely to pierce the wall. This demonstrates that knowing the quantity of the force isn't always enough: you also need to know how that force is distributed over the impact surface. The nail condensed all of the power between the wall and the nail into a relatively tiny region on the pointed tip of the nail. However, because the area of the bowling pin that touched the wall was significantly bigger, the force was much less focused.
Newton's Second Law states that the net Force acting on an object is given by
MA Fnet = MA
The acceleration is given by the ratio of the change in velocity of an object and the time it takes to change velocity.
(Vf - Vi)/T = a
If the vehicles are driving at constant speeds, their velocity change is zero (0).
If the velocity change is zero, the acceleration is also zero (0).
As a result, Fnet = M(0) = 0.
As a result, the net pressures on the automobile and truck are zero.
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Explain why the power of a train's engine must be increased to maintain the speed while travelling up a slope
Answer:
the power (outside) of the train must be increased for the increase in resistance by the weight component.
Explanation:
We analyze the movement of the train at constant speed, on flat ground the force of the motor must counteract the friction force that opposes the movement, therefore to maintain the constant speed the two forces must be of the same magnitude.
When the train goes up a slope, it is subjected to two forces: the friction force that opposes the movement and a component of the weight in the opposite direction to the movement, therefore the power (outside) of the train must be increased for the increase in resistance by the weight component.
A mass of 1.5 kg moves in a circle of radius 25 cm at 2.0 Hz. Calculate:
a) the velocity. b) the acceleration. c) the centripetal force acting on the mass.
Answer:
To solve this problem, you can use the following formulas:
Velocity (v) = 2πr * f
Acceleration (a) = v^2 / r
Centripetal force (F) = ma
In these formulas, r is the radius of the circle, f is the frequency of the circular motion, and m is the mass of the object.
a) To find the velocity of the mass, you can substitute the values given into the formula for velocity:
v = 2πr * f
= 2π(0.25 m) * 2.0 Hz
= 1.57 m/s
So, the velocity of the mass is approximately 1.57 m/s.
b) To find the acceleration of the mass, you can substitute the values given into the formula for acceleration:
a = v^2 / r
= (1.57 m/s)^2 / 0.25 m
= 4.45 m/s^2
So, the acceleration of the mass is approximately 4.45 m/s^2.
c) To find the centripetal force acting on the mass, you can substitute the values given into the formula for centripetal force:
F = ma
= 1.5 kg * 4.45 m/s^2
= 6.68 N
So, the centripetal force acting on the mass is approximately 6.68 newtons.
please help me and give an explanation
Explanation:
The moon orbits the Earth once every 27.322 days. It also takes approximately 27 days for the moon to rotate once on its axis. As a result, the moon does not seem to be spinning but appears to observers from Earth to be keeping almost perfectly still. Scientists call this synchronous rotation
A coil of wire with a current is called a(n)
a.
insulator.
b.
solenoid.
c.
electromagnet.
d.
galvanometer.
Answer:
Hello There!!
Explanation:
The answer is b. solenoid.
the first artificial satellite to orbit the earth was sputnik 1, launched october 4, 1957. the mass of sputnik 1 was 83.5 kg, and its distances from the center of the earth at apogee and perigee were 7300 km and 6610 km, respectively. find the difference in gravitational potential energy for sputnik 1 as it moved from apogee to perigee
The difference in gravitational potential energy for sputnik 1 as it moved from apogee to perigee is 193 kJ.
The gravitational potential energy of an object in orbit around the Earth can be calculated using the equation:
U = -GMm/r
where U is the gravitational potential energy, G is the gravitational constant, M is the mass of the Earth, m is the mass of the object.
The difference in gravitational potential energy as the satellite moves from apogee to perigee can be found by calculating the potential energy at each point and subtracting the two values:
U(apogee) = -(6.67 x 10^-11 N*(m^2)/(kg^2)) * (5.972 x 10^24 kg) * (83.5 kg) / (7300 x 10^3 m)
U(perigee) = -(6.67 x 10^-11 N*(m^2)/(kg^2)) * (5.972 x 10^24 kg) * (83.5 kg) / (6610 x 10^3 m)
U(apogee) = -1.865 x 10^5 J
U(perigee) = -2.058 x 10^5 J
The difference in gravitational potential energy is:
= U(perigee) - U(apogee)
= -2.058 x 10^5 J - (-1.865 x 10^5 J)
= 193 x 10^3 J
So, the difference in gravitational potential energy for Sputnik 1 as it moved from apogee to perigee is 193 kJ.
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How does mass affect the heat that can be absorbed by a substance?
The mass of the material has no influence on specific heat because it is already a quantity represented per unit mass.
Casey Hudson, Drew Karpyshyn, and Preston Watamaniuk created the military science fiction media franchise Mass Effect. The franchise shows a distant future in which humans and many alien civilizations have conquered the known universe utilizing advanced predecessor civilizations' technologies.
The franchise began with a series of video games created by BioWare and released by Electronic Arts. Each iteration combines third-person shooting gameplay with role-playing features. The first three games comprise a trilogy in which the player character, Commander Shepard, strives to defend the Milky Way galaxy from the Reapers, a species of ancient, sleeping robots.
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If I raise the temperature of a material by 5 K, what is the corresponding change in temperature on the Fahrenheit scale?
The corresponding change in temperature on the Fahrenheit scale More than 5°F.
In the Celsius scale, a temperature change of 5 degrees K corresponds to a shift of 50 degrees C. This is due to the fact that a temperature change of one degree Celsius is equivalent to a temperature change of one degree Kelvin. Tk = TC +273.15. We can observe that the relationship between the two temperature scales is linear and that its slope is the same for each.
The degree Celsius, denoted by the symbol °C, is the unit of temperature in Celsius and is by definition equal in magnitude to the kelvin unit. A temperature difference or interval can be stated in either kelvin or degrees Celsius, and in both cases the numerical value of the temperature difference is the same. However, the relationship between the numerical value of a thermodynamic temperature represented in kelvin and a Celsius temperature expressed in degrees Celsius exists.
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difference between reflection of sound, echo and reverberation
Les mélange et le transformations de la matiers
Les molécules sont arrangées autrement, ce qui modifie l'aspect ou l'état de l'espèce chimique. Un mélange est une substance composée de plusieurs espèces chimiques qui ne réagissent pas ensemble, au contraire de la transformation chimique. Il s'agit donc d'une transformation physique, qui ne change pas la matière.
great players like LeBron James and Michael Jordan, due to their muscular bodies and athletic talent, defy against the law of physics true or false
The given statement is false. Due of their athleticism and muscular bodies, exceptional athletes like LeBron James or Michael Jordan transcend the laws of physics.
What is law of physics ?Laws of Physics are by their very nature statements of facts that have been inferred and developed from empirical data. Simply said, physical laws are a technique of categorizing how the world behaves when it comes to "functioning."
What is force?When an object interacts with another object, it experiences a push or pull known as a force. Every time two objects come into contact, a force is applied to each one of them. Actual forces can only be created by interaction.
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Two points, point 1 and point 2, are located inside a region with an electric field pointing to the left, as shown in the figure. 1 50% Part (a) If a proton is moved from point 1 to point 2, how will the potential energy of the charge-field system change? How will the potential change?
If protons move in the direction of the electric field, the electric potential would change, and it decreases, but if you move opposite the field, the potential energy increases.
If the field is directed from lower potential to higher then the direction is taken to be positive. If the field is directed from higher potential to lower potential then the direction is taken as negative. Potential energy can be converted to kinetic energy and vice versa.
Potential energy is the stored energy in any object or system by virtue of its position or arrangement of parts. However, it isn't affected by the environment outside of the object or system, such as air or height.
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Electric potential energy can be maximized when
Answer:
d and f
Explanation:
explain how you would produce a loud sound from the violin
Answer:
The energy of a vibrating string is transmitted through the bridge to the body of the violin, which allows the sound to radiate into the surrounding air. Both ends of a violin string are effectively stationary, allowing for the creation of standing waves.
Explanation:
hello please help i’ll give brainliest
The correct answer is B.Antartica and Australia were one landmass millions of years ago.
Find the magnitude of the electric force between the charges 0.12 C and 0.33 C at a separation of 2.5 m. k=8.99×109N⋅m2/C2.
Answer:
F= k Q1 Q2 / r^2
plug in the numbers
If the absolute temperature of an object is tripled, the thermal power radiated per unit surface area of this object will (assuming that its emissivity is not affected by the temperature change)?
Answer: increase by a factor of 81
A temperature increase of an order of 81 will cause an object's thermal output radiated per unit surface area to double, assuming that its emissivity is unaltered by the temperature change.
By dividing the Planck radiation density by a wavelength interval, you can compute it numerically.The rate of heat transfer through radiation emitted is controlled by the Stefan-Boltzmann law of radiation: Qt=σeAT4 The equation Q t = e A T 4 includes the Stefan-Boltzmann constant, A, the object's surface area, and T, the object's absolute temperature in kelvin.All bodies emit energy W depending on temperature T according to the Stefan-Boltzmann formula W = T4, where emissivity is equal to 1 for black bodies and less than 1 for grey ones, being the Stefan constant.To know more about Temperature here
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Mechanics sometimes use a piece of pipe to lengthen the handle of a wrench when trying to remove a very tight bolt. How does this make it easier for the mechanic to remove the bolt
Answer:
increase the length of the handle from the bolt, the torque will increase even if you have the same force
Explanation:
It allows them to apply more torque to the bolt. Torque is the turning or twisting force that causes rotation, in this case, it's applied to the bolt in an effort to loosen it. By lengthening the handle of the wrench, the mechanic is able to leverage more of their body weight and strength behind the wrench, increasing the torque they are able to apply to the bolt.
When a bolt is very tight, it can be difficult to turn it with a standard wrench. The increased torque provided by the longer handle allows the mechanic to apply more force to the bolt, which can help to loosen it. This can be particularly useful in situations where the bolt is corroded, rusted, or otherwise stuck due to a buildup of debris or other factors.
A RL circuit is driven by an AC generator as shown in the figure. sin(ot) The voltages across the resistor and generator are ??.
O always out of phase O always in phase sometimes in phase and O sometimes out of phase Submit
Sometimes in phase and sometimes out of phase.The voltage across the resistor and generator will depend on the phase difference between the current and voltage in the circuit.
The voltage across the resistor and generator will depend on the phase difference between the current and voltage in the circuit. If the phase difference is 0°, then the voltage across the resistor and generator will be in phase. If the phase difference is 180°, then the voltage across the resistor and generator will be out of phase. In any other scenario, the voltage across the resistor and generator will be somewhere in between in phase and out of phase.
Sometimes in phase and sometimes out of phase.
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Select the correct answer. A van traveling down a slope with a uniform acceleration of 2.15 meters/second2 attains a speed of 20.00 meters/second after 7.00 seconds. What is the initial velocity of the van
Answer:
Initial velocity of the van is 4.95m/s
Explanation:
Acceleration is found using the following formula:
[tex]a=\frac{v-u}{t}[/tex]
where:
a is acceleration ( in meters per second squared)
v is final velocity ( in meters per second)
u is initial velocity ( in meters per second)
t is time ( in seconds)
We know that:
[tex]a = 2.15m/s^{2}[/tex]
[tex]v = 20m/s[/tex]
[tex]t=7s[/tex]
Therefore, we can find the initial velocity by shifting around some values and making [tex]u[/tex] the subject within the acceleration formula by multiplying both sides by [tex]t[/tex]:
[tex]a[/tex] × [tex]t=v-u[/tex]
Followed by:
[tex]u = v-at[/tex]
Now we can substitute in the values we have:
[tex]u = 20-(2.15[/tex] × [tex]7)[/tex]
[tex]u = 20 - 15.05[/tex]
[tex]u=4.95m/s[/tex]
Is any of this right?
A camera draws 0. 25 amps and with 72 ohms. What voltage supply does this camera need?
A camera that draws certain current with specified resistance needs a voltage supply which is calculated to be 18 V.
Given that,
Current i = 0.25 A
Resistance r = 72 ohms
Voltage supply v = ?
From Ohm's law, it is defined that, voltage across the conductor is directly proportional to the current flowing through it. Mathematically, it is represented as v = i r
where,
v is the voltage
i is the current
r is the resistance
Putting in the values, we have,
v = i r
v = 0.25 × 72 = 18 V
Thus, the required voltage supply by the camera is calculated to be 18 V.
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Sound energy is considered a form of kinatic energy because it's carried as vibrating waves. o T. True o F False
Answer:
True
Explanation:
Sound kinetic energy produces moving energy by using longitudinal waves. Sound is caused by the vibrations on or from an object, which is how it is considered a kinetic energy form.
The half life of a radioactive substance is the time taken for the activity to halve. Use the graph to calculate the half life of the radioactive isotope.
Radioactive element which keeps on decaying over the time. Decay of radioactive element always comes under first order kinetics. Therefore the half life time of radioactive substance is 2seconds.
What is half life?Half life tells about the time at which the radioactive material decays to half of its initial concentration.
Mathematically,
half life time=0.693/ rate constant of the decay
The half life of a radioactive substance is the time taken for the activity to halve. Using the graph to calculate the half life of the radioactive isotope, we find that activity that is 3500 so, half of this activity is 17500 which is corresponding to time 2 seconds.
Therefore the half life time of radioactive substance is 2seconds.
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What is the Electromagnetic Spectrum? in your own words
The electromagnetic spectrum is a frequency system that shows the wavelengths and intensities of electromagnetic radiation.
What is the electromagnetic spectrum ?The electromagnetic spectrum is a frequency system that depicts electromagnetic radiation, wavelengths, and photon energies.
The electromagnetic spectrum that is seen as colors: violet, indigo, blue, green, yellow, orange, and red.
Radio waves, microwaves, infrared, optical, ultraviolet, X-rays, and gamma-rays are examples of frequencies found in the electromagnetic spectrum.
Hence, the above definition introduce the electromagnetic spectrum.
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If two objects collide and are stationary, what must the total momentum of the sum of the objects have been before collision?
Explanation:
Concept: In collision between two isolated bodies momentum is always conserved.
Also, if the collision is elastic kinetic energies are also conserved
m1v1i + m2v2i = m1v1f + m2v2f.
and in elastic collision
[tex]½m1v1i^2 + ½m2v2i^2 = ½m1v1f^2 + ½m2v2f^2.[/tex]
Momentum is preserved in collisions between two objects. The initial moment not being zero, the final momentum is not zero. This means both object has to be in motion.
However, it may be possible for one of the objects to be at rest after the collision. For instance, if the masses of the two objects are same, then after a head-on elastic collision the object initially at rest is moving and the object initially moving is at rest.