The magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole is 76.6 N.
To find the kinetic frictional force, we first need to calculate the work done by friction during the fireman's slide. This can be found using the work-energy principle, where the work done equals the change in kinetic energy. The kinetic energy just before landing is given by (1/2)mv2, where m is the mass (86 kg) and v is the velocity (1.4 m/s). The potential energy lost during the descent is mgh, where g is the acceleration due to gravity (9.8 m/s2) and h is the distance (4.0 m). The work done by friction is the difference between the initial potential energy and final kinetic energy. Solving these gives the frictional force as the work done by friction divided by the distance traveled down the pole.
In the formula vy = ayt, what is the value of ay for an object in projectile motion?
–9.8 m/s2
0 m/s2
m/s2
1.0 m/s2
Answer : The correct option is (A) [tex]-9.8\ m/s^2[/tex]
Explanation :
The formula is given as :
[tex]v_y=a_yt[/tex]
Where,
[tex]v_y[/tex] is vertical component of velocity.
[tex]a_y[/tex] is the vertical component of acceleration.
In a projectile motion, the particle moves in a path under the influence of gravity.
So, the vertical component of acceleration is -g i.e acceleration due to gravity.
Hence, the correct option is (a) " [tex]a_y=-9.8\ m/s^2[/tex] ".
How does the mass of an astronaut change when she travels from earth to the moon? how does her weight change?
Answer:
Mass does not change
Weight redueces on the moon
Explanation:
The mass of an object never changes with respect to the astronomical body it is on. The mass of an object is the resistance it provides to a force which is applied.
A 1 kg object is an 1 kg object anywhere in the universe.
Weight is the affect of an astronomical object's gravity on it
[tex]W=mg[/tex]
where,
m = Mass of the object
g = Acceleration due to gravity
[tex]g_e[/tex]=Acceleration due to gravity on Earth = 9.81 m/s²
[tex]g_m[/tex]=Acceleration due to gravity on Moon = 1.62 m/s²
Weight on Earth
[tex]W_e=mg_e\\\Rightarrow W_e=9.81m[/tex]
Weight on Moon
[tex]W_m=mg_m\\\Rightarrow W_m=1.62m[/tex]
Dividing the equations we get
[tex]W_m=\frac{1.62}{9.81}W_e\\\Rightarrow W_m=0.165W_e[/tex]
The weight of the astronaut on the moon will be 0.165 times the weight on Earth.
So, the weight of the astronaut will be reduced on the moon
What is the final speed?
How do you calculate force?
two cars on a straight road at time zero are beside each other. the first car, traveling at speed 30 m/s, is passing the second car, which is traveling at 24 m/s. seeing a cow on the road ahead, the driver of each car starts to slow down at 6.0 m/s^2. find the expression of the velocity of the second car.
Final answer:
To find the expression for the velocity of the second car, consider the motion of both cars separately. The velocity of the second car can be described as v2 = 24 - 6t.
Explanation:
To find the expression for the velocity of the second car, we need to consider the motion of both cars separately.
Let's assume that the first car passes the second car at time t = 0. The position of the first car can be described as x1 = 30t, where t is the time elapsed since the first car passed the second car.
The position of the second car can be described as x2 = (24)t - (1/2)(6)t^2, where the negative term represents the deceleration of the second car due to slowing down at 6.0 m/s^2.
Now, we can find the expression for the velocity of the second car by taking the derivative of its position equation with respect to time: v2 = 24 - 6t.
The velocity of the second car, which starts at 24 m/s and decelerates at 6.0 m/s², can be described by the function v(t) = 24 - 6t. This equation shows how the car's velocity decreases over time. For any given time t, you can calculate the velocity using this expression.
To find the expression of the velocity of the second car, we need to consider its deceleration. The second car's initial velocity is 24 m/s, and it decelerates at a rate of 6.0 m/s². The general equation for the velocity of an object under constant acceleration (or deceleration) is:
v(t) = v₀ + at
Here, v(t) is the velocity at time t, v₀ is the initial velocity, and a is the acceleration (note that since it is deceleration, the acceleration will be negative).
Given:
Initial velocity, v₀ = 24 m/sAcceleration, a = -6.0 m/s²We can substitute these values into the equation:
v(t) = 24 m/s - (6.0 m/s²) * t
So, the expression for the velocity of the second car as a function of time is:
v(t) = 24 - 6t
What are characteristics of a moist, unstable air mass?
A moist, unstable air mass is an air mass that has a high moisture content, Low density and Warm temperatures.
Explanation:
A moist, unstable air mass is an air mass that has a high moisture content and is not very dense. This means that the air molecules are not very tightly packed together, which makes it easier for them to rise and form clouds and precipitation.
Here are some of the characteristics of a moist, unstable air mass:
High moisture content: The air mass has a high moisture content, which means that it contains a lot of water vapor.Low density: The air mass is not very dense, which means that the air molecules are not very tightly packed together.Warm temperatures: The air mass is typically warm, which means that the water vapor can easily evaporate and form clouds.Turbulence: The air mass is often turbulent, which means that there are strong winds and eddies that can help to mix the air and promote cloud formation.Find more exercises on unstable air;
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Isaac Newton’s investigations of gravity explained which truth?
A.Earth is not the center of the universe.
B.Jupiter has more moons than Earth.
C.Gravity acts on all objects in the universe.
D.The sun is more massive than Earth.
Answer:
c gravity acts on all objects in the universe
Explanation:
If the distance from the moon to the satellite is 2.6 × 106 m, what is the mass of the satellite?
HELP
450kg would be your answer.
Hope it helped you.
Answer:
450
Explanation:
Which of the following best describes what went wrong with the scientists’ study? an improper experimental procedure the lack of a control group selection bias human error
Newton Calculation Error
in the book "Principia Mathematica" contains a simple calculation error that was not discovered for 300 years. Errors occur in Proposition Eight, where Newton presents a formula for calculating the mass of the planet, involving angles formed by two specific lines.
Further explanation
The mistakes made by scientists:
Galileo's Tidal TheoriesHe was wrong from the start, starting his efforts to explain the tidal movements with a false premise - namely that it was caused by the rotation of the earth around the sun. This means the theory is incorrect because it is based on mistakes.
Darwin and the Theory of HeredityOne problem with Darwin's original theory concerns heredity. Many people have a misconception about how characteristics are passed down from parents to their children. The problem is that this notion of mixed genetics contradicts Darwin's own theory. If that is true, then the characteristics will not change from generation to generation through natural selection.
Triple helix from Linus PaulingDespite getting the Nobel Prize, Pauling admitted there was an error in his discovery. The model is wrong for a very simple reason: This includes the triple helix. He also made a basic mistake in his calculations, and the nucleic acid molecule in his model was actually not acidic.
Edwin Hubble's Universe CalculationsAccording to Hubble, the universe is two billion years old. This statement is proven wrong. In the 1930s, a study said the earth was between three and five billion years old. Obviously, our planet cannot be older than the universe, so something's wrong with Hubble.
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Class: High School
Subject: Physics
Keywords: scientist, mistake, newton
If an electron loses energy what may happen to it
Will give 15 points.
Name three different kinds of graphs that are often used to plot information and discuss the value of each.
The three different kinds of graphs that are often used to plot information are Bar graphs, Pie charts, and Line graphs.
What is a graph?A graph is a way to represent a lot of data in such a visual format that it is easy for the user to understand the complete information in one go. Usually, the line of the graph is a function that follows the graph.
The three different kinds of graphs that are often used to plot information are,
Bar graphs: It is used to display numbers that are unrelated to one another. Data examples may include the number of persons who liked Chinese takeaways, Indian takeaways, and fish & chips.Pie charts: These are used to demonstrate how a whole is split into separate portions. For example, You could wish to display how a budget was spent on various items in a given year.Line graphs: Line graphs demonstrate how data has evolved throughout time. They are used when you have linked data and want to display patterns, such as the average night-time temperature in each month of the year.Hence, the three different kinds of graphs that are often used to plot information are Bar graphs, Pie charts, and Line graphs.
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The light-gathering power of a 4-meter telescope is ________ than that of a 2-meter telescope.
Final answer:
The light-gathering power of a 4-meter telescope is significantly greater than that of a 2-meter telescope due to the proportional increase in aperture area, allowing it to collect four times as much light.
Explanation:
The light-gathering power of a 4-meter telescope is significantly greater than that of a 2-meter telescope. This is because the light-gathering ability of a telescope is determined by the area of its aperture (the mirror or lens that collects light), and this area increases with the square of the diameter of the aperture. Therefore, a 4-meter diameter telescope has an aperture area that is 4 times larger than that of a 2-meter diameter telescope, allowing it to gather significantly more light.
To illustrate, if a 1-meter telescope collects a certain amount of light, a 4-meter telescope, with 16 times the area, would collect 16 times as much light. Similarly, compared to a 2-meter telescope, a 4-meter telescope, having an area four times greater (since the area is proportional to the square of the diameter), can collect four times as much light.
Suppose you increase your walking speed from 5 m/s to 15 m/s in a period of 1 s. What is your acceleration?
Pitch describes the loudness of a sound.
True False?
A skier with a 65kg mass skies down a 30 degree incline hill. The coefficient of friction is 0.1. a. Draw a free body diagram. b. Determine the normal force. c. Determine the acceleration of the skier down the hill.
To draw a free body diagram for the skier, identify the forces acting on the skier including the gravitational force, normal force, and frictional force. The normal force can be found by taking the component of the gravitational force perpendicular to the incline. The acceleration of the skier down the hill can be determined using Newton's second law.
Explanation:To draw a free body diagram for the skier, we need to identify the forces acting on the skier. These include the gravitational force (mg) acting straight down, the normal force (N) perpendicular to the incline, and the frictional force (f) parallel to the incline. The acceleration of the skier down the hill can be determined using Newton's second law, which states that the net force (Fnet) equals the mass (m) times the acceleration (a): Fnet = ma.
The normal force can be found by taking the component of the gravitational force perpendicular to the incline, which is given by N = mg*cos(theta).
The acceleration of the skier down the hill can be determined using the equation Fnet = ma, where the net force is the difference between the gravitational force parallel to the incline and the frictional force: Fnet = mg*sin(theta) - f.
The normal force acting on the skier is approximately 550.32 N.The skier's acceleration down the hill is approximately 3.03 m/s².
Here's how to solve the problem:
a. Free body diagram:
The free body diagram for the skier should show the following forces acting on them:
Weight (mg): This is the force of gravity acting on the skier, directed downwards. Its magnitude is given by `mg`, where `m` is the skier's mass (65 kg) and `g` is the acceleration due to gravity (approximately 9.81 m/s²). In this case, the weight would be `65 kg * 9.81 m/s² ≈ 637.65 N`.
Normal force (N): This is the force exerted by the slope on the skier, perpendicular to the slope. Its magnitude depends on the weight and the angle of the slope.
Friction force (f): This is the force opposing the skier's motion, parallel to the slope. Its magnitude is proportional to the normal force and the coefficient of friction (`μ`).
b. Normal force:
The normal force can be calculated using the component of the weight perpendicular to the slope. This can be done using trigonometry:
N = mg * cos(θ)
where `θ` is the angle of the slope (30° in this case).
Therefore, the normal force would be:
N = 637.65 N * cos(30°) ≈ 550.32 N
c. Acceleration:
The acceleration of the skier can be calculated using Newton's second law of motion:
ΣF = ma
where `ΣF` is the net force acting on the skier, `m` is the skier's mass, and `a` is the acceleration.
The net force is the difference between the downhill component of the weight and the friction force:
ΣF = mg * sin(θ) - μ * N
Substituting the known values:
ΣF = 637.65 N * sin(30°) - 0.1 * 550.32 N ≈ 196.81 N
Finally, solving for the acceleration:
a = ΣF / m = 196.81 N / 65 kg ≈ 3.03 m/s²
Therefore, the skier's acceleration down the hill is approximately 3.03 m/s².
An analogy makes a comparison between objects based on their similar qualities. Cassidy wanted to create an analogy for the motion of atoms in solids, liquids, and gases, so she compared them to marbles in a tray. Which best compares the phases of matter to marbles in a tray? A solid is like the tray being shaken and the marbles moving around it, and a liquid is like the tray being shaken slowly and all the marbles moving in their positions. A solid is like the tray being shaken slowly and all the marbles moving in their positions, a liquid is like the tray being shaken and the marbles moving around it, and a gas is like the tray being shaken hard and the marbles moving vigorously around it. A gas is like the tray being shaken slowly and all the marbles moving in their positions, and a solid is like the tray being shaken hard and the marbles moving vigorously around it. A liquid is like the tray being shaken hard and the marbles moving vigorously around it, and a gas is like the tray being shaken slowly and all the marbles moving in their positions.
Answer:
The answer is b for anyone wondering.
Explanation:
A train travels 120km in 2 hours and 30 minutes what is the average speed
A 7.00 g bullet, when fired from a gun into a 0.80 kg block of wood held in a vise, penetrates the block to a depth of 8.20 cm. this block of wood is next placed on a frictionless horizontal surface, and a second 7.00 g bullet is fired from the gun into the block. to what depth will the bullet penetrate the block in this case?
To determine the depth to which the second bullet will penetrate the block, we can use the work-energy theorem. By comparing the initial kinetic energy of the bullet-block system to the work done by the average stopping force in each situation, we can find the depth.
Explanation:The initial situation is when a 7.00 g bullet is fired into a 0.80 kg block of wood held in a vise. The bullet penetrates the block to a depth of 8.20 cm. In the second situation, the block of wood is placed on a frictionless horizontal surface, and a second 7.00 g bullet is fired into the block. The question asks to determine the depth to which the bullet will penetrate in this case.
To solve this problem, we can use the work-energy theorem. Since the wood block is on a frictionless horizontal surface, there is no external force doing work on the block-bullet system. Therefore, the initial kinetic energy of the bullet is equal to the work done by the average stopping force in stopping the bullet. We can equate these two and solve for the unknown depth.
In the initial situation, the bullet penetrated to a depth of 8.20 cm. We can use this known value along with the mass of the bullet and the mass of the block to find the initial kinetic energy of the bullet-bloc system. Then, we can set this initial kinetic energy equal to the work done by the average stopping force in the second situation to find the depth to which the bullet will penetrate.
WILL MARK AS BRAINLIEST
You plug in an extension cord and have to be very careful around the electrical outlet. However, you can handle the extension cord without worry of being shocked by the electrical charge. Which statement best explains why you can do this?
A. The cord is made of a combination of materials, which are good conductors of electricity. The combination of two conductors directs the flow of electricity away from you and down the cord.
B. The extension cord is made of plastic which only conducts electricity for a certain period of time. If you handle the cord, the electricity passes through it so fast that you are not in danger of being shocked.
C. The extension cord is made of copper wire, which is a good conductor of electricity; however, it is covered with plastic, an insulator, which does not allow the electrical current to flow to you.
D. The cord has a plastic cover, which is a good conductor of electricity so it carries the electrical current away from your hand, which is an insulator.
Answer:
The answer is C
Explanation:
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1. What conditions must be met for information to be considered true science?
2. How do scientific laws and theories differ?
3. Is it possible for a scientific theory to become a law? Why or why not?
Question 4 of 20 : Select the best answer for the question. 4. Which of the following would lower the pitch of a string instrument's sound? A. shortening the effective string length. B. increasing the thickness of the string used. C. adding tension within the string. D. using less force to vibrate the string
A light year is _____.
A. the distance light travels in a year
B.the distance travels in a day
C. the amount of time it takes light to get to the nearest star
Which of the following is a supersonic speed? Mach 0.005 Mach 0.05 Mach 0.5 Mach 5
I just had this question, the correct answer is March 5
Which one is greater than a liter?
kiloliter?
milliliter?
megaliter?
centiliter?
deciliter?
nanoliter?
According to the law of conservation of energy, energy cannot be created or destroyed, it can only be
a. True
b. False
The difference in ________ of p and s waves provides a method for determining the epicenter of an earthquake.
It takes 200 n to move a box 10 meters in 8 seconds. how much power is required?
The answer is 250 W
Apex
After traveling for 3.0 seconds, a dog reaches a speed of 15 m/s. what is the dog's acceleration?
What happens to the particles of a gas when the gas turns into a liquid?
A.the particles are melting
B.the particles are boiling
C.the motion of the particles is slowing down
D.the motion of the particles is speeding up
What causes the moon's phases?
a. the rotation of the moon on its axis
b. earth's tilt on its axis as it revolves around the sun
c. changes in how much of the sunlit side of the moon faces earth.
d. the position of the moon each month in relation to?
C.
Changes in how much of the sunlit side of the moon faces Earth