Answer:
1 meter per second
Explanation:
Every second, he walks 1 meter because 15 ÷ 15 = 1
A physics student of mass 43.0 kg is standing at the edge of the flat roof of a building, 12.0 m above the sidewalk. An unfriendly dog is running across the roof toward her. Next to her is a large wheel mounted on a horizontal axle at its center. The wheel, used to lift objects from the ground to the roof, has a light crank attached to it and a light rope wrapped around it; the free end of the rope hangs over the edge of the roof. The student radius 0.300 m and a moment of inertia of 9.60 kg m^2 for rotation about the axle, how long does it take her to reach the side walk, and how fast will she be moving just beofre she lands?
Answer:
The speed of the student just before she lands, v₂ is approximately 8.225 m/s
Explanation:
The given parameters are;
The mass of the physic student, m = 43.0 kg
The height at which the student is standing, h = 12.0 m
The radius of the wheel, r = 0.300 m
The moment of inertia of the wheel, I = 9.60 kg·m²
The initial potential energy of the female student, P.E.₁ = m·g·h₁
Where;
m = 43.0 kg
g = The acceleration due to gravity ≈ 9.81 m/s²
h = 12.0 h
∴ P.E.₁ = 43 kg × 9.81 m/s² × 12.0 m = 5061.96 J
The kinetic rotational energy of the wheel and kinetic energy of the student supporting herself from the rope she grabs and steps off the roof, K₁, is given as follows;
[tex]K_1 = \dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex]
The initial kinetic energy, 1/2·m·v₁² and the initial kinetic rotational energy, 1/2·m·ω₁² are 0
∴ K₁ = 0 + 0 = 0
The final potential energy of the student when lands. P.E.₂ = m·g·h₂ = 0
Where;
h₂ = 0 m
The final kinetic energy, K₂, of the wheel and student is give as follows;
[tex]K_2 = \dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]
Where;
v₂ = The speed of the student just before she lands
ω₂ = The angular velocity of the wheel just before she lands
By the conservation of energy, we have;
P.E.₁ + K₁ = P.E.₂ + K₂
∴ m·g·h₁ + [tex]\dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex] = m·g·h₂ + [tex]\dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]
Where;
ω₂ = v₂/r
∴ 5061.96 J + 0 = 0 + [tex]\dfrac{1}{2} \times 43.0 \, kg \times v_{2}^2+\dfrac{1}{2} \times 9.60 \, kg\cdot m^2 \cdot \left (\dfrac{v_2}{0.300 \, m} }\right ) ^2[/tex]
5,061.96 J = 21.5 kg × v₂² + 53.[tex]\overline 3[/tex] kg × v₂² = 21.5 kg × v₂² + 160/3 kg × v₂²
v₂² = 5,061.96 J/(21.5 kg + 160/3 kg) ≈ 67.643118 m²/s²
v₂ ≈ √(67.643118 m²/s²) ≈ 8.22454363 m/s
The speed of the student just before she lands, v₂ ≈ 8.225 m/s.
How do you calculate kinetic energy without velocity
The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.
Kinetic energy (KE) is calculated using the formula:
KE = (1/2) × mass × velocity²
However, if you don't have the velocity value, it is not possible to calculate the kinetic energy accurately. Velocity is a crucial component in determining kinetic energy because it quantifies the object's speed and direction of motion.
But there is a special case when the object is at rest the change in velocity is equal to the work done.
Therefore, The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.
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In the diagram below, what is the potential difference across the 3.0-ohm resistor?
Answer:
3V
Explanation:
From the question given above, we can see clearly that the resistors are arranged in parallel connection. Hence, the same voltage will pass through the resistors i.e
Total voltage = voltage of 3 Ω = voltage of 6 Ω
From the question given above,
The total voltage = 3 V
Therefore,
Voltage of 3 Ω = total voltage
Voltage of 3 Ω = 3V
Thus, option 3 gives the correct answer to the question.
A 15.0 cm object is 12.0 cm from a convex mirror that has a focal length of -6.0 cm. What is the height of the image produced by the mirror?
–5.0 cm
7.5 cm
-7.5 cm
5.0 cm
Answer:
-7.5
Explanation:
edge 2021
An object has an acceleration of 18.0 m/s/s. If the net force acting upon this object were doubled, then its new acceleration would be m/s/s.
Answer:
36.m/s/s
Explanation:
A ramp that is 8 meters long raises an object 2meters. What is the mechanical advantage
Why isn't nuclear fusion used to generate electric energy in power plants?
A.
It requires extremely high pressure.
B.
It uses a very rare radioactive isotope.
C.
It releases less energy per gram than uranium does.
D.
It requires converting matter into energy.
Answer:
A) It requires extremely high pressure.
Explanation:
The reasons why we haven't been able to harness power from fusion is that its energy requirements are unbelievably, terribly high.
The correct statement is: "nuclear fusion requires extremely high pressure."
To find the correct statement among all the options, we need to know about nuclear fusion.
What is nuclear fusion?
Nuclear fusion is a nuclear reaction in which nuclei are fused to form another nucleus and releases some energy.How much pressure is required for nuclear fusion?
In a nuclear fusion reaction, 250 billions atmospheric pressure is required. One atmospheric pressure is 101325 pascals.Creating this much pressure is very much difficult.How much energy is released during nuclear fusion?
In nuclear fusion, 17.6 MeV energy is released in a single reaction. Since, two hydrogen atoms are participated, so energy released per nucleon is 8.8 MeV.What is the comparison of energy that released in nuclear fusion and fission?
In a nuclear fission reaction, 200 MeV energy is released in a single reaction and energy per nucleon is less than 1 MeV as an uranium has 238 nucleons.So, nuclear fusion reaction releases more energy as compared to that of nuclear fission.How does we get energy in the nuclear fusion reaction?
In a nuclear fusion reaction, two hydrogen atoms are fused to form a helium atom and the energy is released due the binding energy differences of hydrogen and helium atoms.Thus, we conclude that option (A) is correct.
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A plane is flying with an airspeed of 190 miles per hour and heading 150°. The wind currents are running at 30 miles per hour at 170° clockwise from due north. Use vectors to find the true course and ground speed of the plane. (Round your answers to the nearest ten for the speed and to the nearest whole number for the angle.)
Answer:
[tex]Vg=200mile/hr[/tex]
[tex]\theta=153 \textdegree[/tex]
Explanation:
From the question we are told that:
Plane airspeed [tex]v_p=190mil/h[/tex]
Plane direction [tex]\angle=150 \textdegree[/tex]
Wind current speed [tex]V_w=30mil/h[/tex]
Wind direction [tex]\angle=150 \textdegree[/tex]
Generally the vector form of the forces is mathematically given by
For plane
[tex]\angle Q_p=90-150 \textdegree[/tex]
[tex]V_p=170(cos60 \textdegree ,sin60 \textdegree)[/tex]
[tex]V_p=(85,-147.224)[/tex]
For wind
[tex]\angle Q_w=90-170 \textdegree[/tex]
[tex]V_w=30(cos-80 \textdegree ,sin-80 \textdegree)[/tex]
[tex]V_w=(5.2,-29.54)[/tex]
Generally the equation for resultant force is mathematically given by
[tex]v_r=V_a+V_w[/tex]
[tex]v_r=(85,-147.224)+(5.2,-29.54)[/tex]
[tex]v_r=(90.21,-176.76)[/tex]
[tex]v_r=198.45\angle -63[/tex]
Therefore ground speed
[tex]V_g=198.5miles/hr[/tex]
[tex]Vg=200mile/hr[/tex]
Direction
[tex]\theta=(90+63)=153 \textdegree[/tex]
[tex]\theta=153 \textdegree[/tex]
6. A tuning fork, frequency 384 Hz, produces resonance with a closed tube 20.0 cm long. What is the speed of sound?
7. What is the frequency of a tuning fork that resonates with an open tube 25.0 cm long. Speed of sound that day is 343 m/s
Please show the work
Answer:
6. Speed = 76.8 m/s
7. Frequency = 1372 Hz
Explanation:
Given the following data;
6. Frequency = 384 Hz
Wavelength = 20 cm to meters = 20/100 = 0.2 m
To find the speed of sound;
Speed = wavelength * frequency
Speed = 0.2 * 384
Speed = 76.8 m/s
7. Wavelength = 25 cm to meters = 25/100 = 0.25 m
Speed = 343 m/s
To find the frequency of the turning fork;
Frequency = speed/wavelength
Frequency = 343/0.25
Frequency = 1372 Hz
A ball on a string is swung in a horizontal circle at a constant speed of 4.3m/s. The centripetal acceleration of the ball is 24.7 m/s^2. The mass of the ball is 3.2kg.
What is the length of the string?
Please show all work thank you so much!
The length of the string is 75 cm.
What is centripetal acceleration?Centripetal acceleration is a characteristic of an object's motion along a circular path. Centripetal acceleration applies to any item travelling in a circle with an acceleration vector pointing in the direction of the circle's center.
Given that: The centripetal acceleration of the ball is: a = 24.7 m/s^2.
constant speed of the ball is: v = 4.3m/s.
Let the length of the string is l.
We know that: The centripetal acceleration: a = v^2/l
l = v^2/a
= (4.3)^2/24.7
= 0.75 m.
Hence, the length of the string is 0.75 m or 75 cm.
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Does anbody know?????
Answer:
it is B
Explanation:
it is a compound lol
what is the velocity of a car that went a distance of 400ft in 25 seconds
Speed = (distance covered) / (time to cover the distance)
Speed = (400 ft) / (25 seconds)
Speed = 16 ft/sec
That's the car's speed.
We don't have enough information to state its velocity.
The tendency to pull other objects toward it is called
Answer:
""gravity. the force that pulls on objects and causes acceleration if the objects are not balanced by an opposing force. speed. distance traveled per unit time. Newton's Second Law of Motion.""
Explanation:
How does friction affect the output of machines?
Answer:
In a machine, friction reduces the mechanical advantage, or the ratio of output to input: an automobile, for instance, uses one-quarter of its energy on reducing friction. Yet, it is also friction in the tires that allows the car to stay on the road, and friction in the clutch that makes it possible to drive at all
Explanation:
hope it will help you
Objects which stay at one place under water, neither sinking or floating, are said to have what kind of buoyancy? Neutral, negative, or positive
Answer:
Neutral
Explanation:
The buoyant force balances the force of gravity when the average density of an object is equal to the density of the fluid in which it is immersed, resulting in the object sinking (if its density is greater than the density of the fluid) or rising (if it is less). Neutral buoyancy occurs when the average density of an object equals the density of the fluid in which it is immersed. There is no sinking or rising for an object with neutral buoyancy.
Koby placed ½ teaspoon of baking soda into each of two identical glasses. He noticed the baking soda was lumpy, so he used a fork to break up the lumps. Why is it important to break up the lumps?
Answer:
because the lumps are just baking soda covered with whatever watery substance you used.
Explanation:
so pretty much inside the lumps is just a bunch of baking soda
PLEASE I NEED HELP from an actual person who isn't going to give me links to hack me :(
Differentiate the between, Heat, Thermal Energy, and Temperature.
Thermal energy refers to the energy contained within a system that is responsible for its temperature. Heat deals with the flow of thermal energy. Temperature is the physical manifestation of thermal energy, and deals with whether it feels cold or hot.
Which image best illustrates diffraction?
Answer:
The first option- Sun shining through clouds
Explanation:
which best illustrates the relationships between a producer and a consumer
If a species experiences a helpful mutation, like camouflage, explain how that mutation would help the species to better I survive and flourish. Again, be sure to explain how and why that mutation would be helpful.
HELP I NEED IT FAST PLEASE ILL MARK B!!!! IF CORRECT
The diagram shows a roller-coaster track. Assume that the system is closed.
At point E, the roller-coaster car has just exited the vertical loop.
Which statement best describes the relative amounts of potential and kinetic
energy of a roller-coaster car at point E?
O A. Kinetic energy is at almost 0%, and potential energy is at almost
100%
O B. Both kinetic and potential energy are at almost 0%.
O C. Both kinetic and potential energy are at almost 100%.
OD. Potential energy is at almost 0%, and kinetic energy is at almost
100%
Answer: Potential energy is at almost 0%, and kinetic energy is at almost 100%
Explanation: took the exam
The roller coaster will lost its potential energy when its starts to excite the vertical loop and its kinetic energy will be maximum. Hence, option D is correct.
What is kinetic energy?Kinetic energy of a body is generated by its motion. Kinetic energy is proportional to the mass and square of the velocity of the object. Thus, as the speed of the object increase, kinetic energy increases.
Potential energy of a body is generated by virtue of its position. When a moving body slows down to stop, it gains potential energy and its kinetic energy starts decreasing.
When the roller coaster excites the vertical loop of the closed path, it loses its potential energy and kinetic energy increases to maximum since its moving the down loop with greater velocity. Thus, option D is correct.
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Which statement describes one way that nuclear fission differs from nuclear fusion?
A. Nuclear fission can be sustained only in the Sun and other stars.
B. Nuclear fission can occur spontaneously.
C. The temperature required for nuclear fission is more than 15 million degrees Celsius.
D. It is more difficult to start and control nuclear fission,
Answer:
it is B
Explanation:
B
Statement B describes one way that nuclear fission differs from nuclear fusion in that nuclear fission can occur spontaneously.
What is nuclear power?The utilization of nuclear reactions to generate energy is known as a nuclear power. Nuclear fission, nuclear decay, and nuclear fusion processes are all sources of nuclear energy.
Nuclear power facilities currently produce the great bulk of the electricity generated by nuclear fission of uranium and plutonium.
Statement B describes one difference between nuclear fission and nuclear fusion in that nuclear fission can occur spontaneously.
Hence,option B is correct.
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Imagine you leave the dock on a fishing boat that travels east for 30 kilometers when the captain realizes he left the fishing rods on the dock. It takes him 40 minutes to travel out against the current but only 20 minutes to return to the dock.
Answer:
Average speed is 60 km/hr whereas average velocity is 0 km/ hr.
Explanation:
The average speed of the boat is 60 km/ hr while on the other hand, the average velocity of the boat is 0 km/ hr because average speed is the total distance covered by the boat in total time and average velocity is the displacement covered by the boat in total time. The total distance covered by the boat is 60 km and the total time is 60 minutes which is equals to one hour so the answer is 60 km/hr whereas the displacement is the shortest distance between initial and final position which is 0 in this case so 0 divided by 60 minutes or one hour is also 0.
Calculate the charge if one miliAmp flows for 1 second
Answer:
Thus 1 Ampere is the current is defined as flow of 1 coulomb charge through a conductor in 1 second.
Explanation:
Hope it helps
Suppose a blanket has a sock stuck to it due to static electricity. When you pull the sock off of the blanket, what happens to the potential energy between them?
Explanation:
When you pull the sock off of the blanket, the socks gain electrons out of blanket. This makes socks slightly negatively charged. The potential energy of the socks rise whereas potential energy of the blanket reduces. This happens because of exchange of electrons between socks and blanket.
If the driver slammed on the brakes, what could happen to the crate?
Please help please real quick
Answer:
1. (a) The final velocity is 20 m/s
(b) The distance travelled is20 meters
2. The distance travelled by the train in the 30 seconds is 825 meters
3. The most correct option is;
(d) 53 km
4. The heat, developed by the electric iron is 15,000 joules
5. a) In the first network the resistance between A and B is 2 Ω
b) In the second network the resistance between A and B is 4Ω
c) In the third network the resistance between A and B is 6Ω
d) In the fourth network the resistance between A and B is 2Ω
Explanation:
1. (a) The parameters of the cheetahs motion are;
The initial motion (velocity) of the cheetah = 0 m/s (The cheetah starts from rest)
The acceleration of the cheetah, a = 2 m/s²
The duration of the acceleration of the cheetah, t = 10 seconds
The kinematic equation of the motion of uniform acceleration, of the cheetah can be written in the following form;
v = u + a·t
s = u·t + 1/2·a·t²
Where;
v = The final velocity
u = The initial velocity = 0 m/s
a = The acceleration of the cheetah = 2 m/s²
s = The distance traveled
∴ v = 0 + 2 × 10 = 20
The final velocity, v = 20 m/s
(b) From s = u·t + 1/2·a·t², we have;
s = 0 × 10 + 1/2 × 10 × 2² = 20
The distance travelled, s = 20 meters
2. The given details of the motion of the train are;
The initial velocity of the train, u = 20 m·s⁻¹
The acceleration of the train, a = 0.5 m·s⁻²
The duration of the train's acceleration, t = 30 seconds
Therefore, the distance travelled, 's', is given by; s = u·t + 1/2·a·t²
∴ s = 20 × 30 + (1/2) × 0.5 × 30² = 825
The distance travelled by the train in the 30 seconds, s = 825 meters
3. The given distance the truck covers with the average speed of 80 km/h, d₁ = 40 km
The distance the truck then covers with the average speed of 40 km/h, d₂ = 40 km
[tex]Average \ speed = \dfrac{Total \ distance}{Time}[/tex]
[tex]\therefore time, \, t = \dfrac{Total \ distance}{Average \ speed}[/tex]
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(80 km·h) t₁ = 0.5 hour
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(40 km·h) t₂ = 1 hour
The total time taken to cover both 40 km distances, t = t₁ + t₂
∴ The total time taken to cover both 40 km distances, t = (0.5 + 1) hour = 1.5 hours
The total distance covered at both speeds, d = d₁ + d₂
∴ d = 40 km + 40 km = 80 km
The average speed of the truck for the total distance, [tex]v_{average}[/tex] = d/t
∴ [tex]v_{average}[/tex] = 80 km/1.5 hours = 53.[tex]\overline 3[/tex] km/h ≈ 53 km/h
The average speed of the truck for the total distance, [tex]v_{average}[/tex] ≈ 53 km/h
The correct option is (d) 53 km
4. The heat, 'H', developed by the electric iron is given by the following formula;
H = I²·R·t
Where;
I = The current flowing in the electric iron = 5 A
R = The resistance of the iron = 20Ω
t = The time duration of the flow of the current = 30 s
∴ H = (5 A)² × 20 Ω × 30 s = 15,000 joules
The heat, developed by the electric iron, H = 15,000 joules
5. Let 'R' represent the resistance between A and B in each network
a) For the first network, we have;
1/R = 1/(2 + 2) + 1/(2 + 2) = 1/4 + 1/4 = 1/2
∴ R = 2 Ω
∴ The resistance between A and B is 2 Ω
b) For the second network, we have;
R = 1/(1/2 + 1/2) + 3 = 4
R = 4Ω
∴ The resistance between A and B is 4 Ω
c) For the third network, we have;
R = 2 + 1/(1/4 + 1/4) + 2 = 6
R = 6Ω
∴ The resistance between A and B is 6 Ω
d) For the fourth network, we have;
R = 1/(1/2 + 1/2) + 1/(1/2 + 1/2) = 2
R = 2Ω
∴ The resistance between A and B is 2 Ω
Atoms that have a positive charge will be attracted to atoms with a
charge. *
O Positive
O Negative
O Neutral
Answer:
negative
Explanation:
positive charges attract negative charges and vice versa. and are possible to nullify
______________ controls the flow of electric current.
Answer!!!
Please
Answer:
Explanation:
Its resistor
Paula is sailing across a lake. As the boat accelerates, she thinks about how
the wind is pushing on the sail. Which statement below best represents
what is happening between the sail and the air?
A. The sail is pushing the wind back and slowing down the air.
B. The sail and air are not pushing each other, they are just moving together.
C. The air is pushing on the sail, but the sail is not pushing the air.
D. The sail is pushing the wind forward with the air.
Which statement do you most agree with? Explain you reasoning.
The answer is (A.) The sail is pushing the wind back and slowing down the air. The wind is pushing the sail and the sail pushes the wind back and slows the air down.
As the boat is sailing, the wind will be faster than the boat. This fast wind is obstructed by the sail. That is, the fast wind gets slowed down by the sail because the sail pushes the wind backwards which slows down the wind. This will make the wind push the boat forward thereby accelerating the boat.
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