Which one of the following indicates a drop in temperature? A. The alcohol in a thermometer expands. B. The brass on a bent bimetallic strip is on the outside curve. C. The column of liquid in a thermometer moves up three degrees. D. A bimetallic strip bends so that the steel is on the outside curve.
Answer:
A bimetallic strip bends so that the steel is on the outside curve.
Explanation:
A bimetallic strip is a combination of two different metals. The linear coefficient of expansion of various metals are different, depending on their characteristics. For example, when a bimetallic strip of brass and steel are taken, thermal expansion coefficient of brass is more than that of steel.
That implies brass expands more than steel, for a given amount of heat supplied. So brass will curve outward since it becomes longer compared to steel. Steel will curve inwards.
Similarly, for cooling process where a drop in the temperature occurs, brass contracts more compared to steel and so Steel will be on outside curve.
The color that we see when looking at a pigmented object is ______.
a. the wavelengths that are reflected or transmitted by the pigmented object
b. the wavelengths that have been raised to an excited state by the pigmented object
c. the wavelengths that are absorbed by the pigment
d. the wavelengths that the pigmented object created after interacting with sunlight
It was a dark and stormy night, when suddenly you saw a flash of lightning. Three-and-a-half seconds later you heard the thunder. Given that the speed of sound in air is about 340 m/s, how far away was the lightning bolt?
Final answer:
To find the distance of the lightning bolt, multiply the speed of sound (340 m/s) by the time delay between seeing the flash and hearing the thunder (3.5 seconds), resulting in a distance of 1190 meters.
Explanation:
To calculate the distance of the lightning bolt, we will use the information that the speed of sound in air is about 340 meters per second (m/s). When you count the time from seeing the lightning to hearing the thunder, this time difference is due to the fact that light travels much faster than sound and reaches us almost instantaneously. Here are the steps for the calculation:
First, note the time lag between seeing the lightning and hearing the thunder, which is 3.5 seconds.Since we know that sound travels at 340 m/s, we can use the formula distance = speed × time.Now, multiply the speed of sound by the time lag: 340 m/s × 3.5 s = 1190 m.Therefore, the lightning bolt was 1190 meters away from you.A car travels 10.0 m/s. What is its velocity in km/h?
A. 0.6 km/h
B. 36,000 km/h
C. 36 km/h
D. 360 km/h
After creating a question and forming a hypothesis, what is the next step in the scientific method
In an internal combustion engine, the gas vapor/air mixture enters the cylinder during the _____ stroke.
Which planet is closest to earth in diameter mass and strength of gravity?
Young people do have the ability to initiate a positive change in their community. Depending where they live they could always give back by completing some type of community service. Some examples are setting up a beach or park clean-up, volunteering at a soup kitchen or organizing a fundraiser or a food drive for the local homeless shelter.
A object is placed in front of a convex mirror. The image that forms is .
The answer is virtual.
Explanation:
The image formed by convex mirror is virtual and erect always.
Let's consider two cases :
(1) When the object is placed at infinity, the image will be formed at the focus and behind the mirror. A point sized image will form and its nature is virtual and erect.
(2) When the object is placed anywhere from infinity to pole of the mirror, then the image will form between pole and focus. Its size is diminished and nature is virtual and erect again.
A stone is dropped from a tower 100 meters above the ground. The stone falls past ground level and into a well. It hits the water at the bottom of the well 5.00 seconds after being dropped from the tower. Calculate the depth of the well. Given: g = -9.81 meters/second2.
A ball is dropped off of a tall building and falls for 2 seconds before landing on a balcony. a rock is then dropped from the top of the building and falls for 4 seconds before landing on the ground. how does the final speed (meaning the speed it had just before landing) of the rock compare to the final speed of the ball?
Final answer:
The final speed of the rock is greater than that of the ball because the rock falls for a longer time, resulting in a final speed that is twice as much as that of the ball when comparing the times of 2 seconds and 4 seconds of free fall under gravity.
Explanation:
To compare the final speeds of the ball and the rock dropped from the same building, but at different times, we will use the equation of motion under constant acceleration due to gravity, which is v = u + at, where v is the final velocity, u is the initial velocity (zero in this case, since both objects are dropped), a is the acceleration due to gravity (9.81 m/s2), and t is the time in seconds.
For the ball that falls for 2 seconds:
v = 0 + (9.81 m/s2) * (2 s)v = 19.62 m/sFor the rock that falls for 4 seconds:
v = 0 + (9.81 m/s2) * (4 s)v = 39.24 m/sThus, the final speed of the rock is greater than the final speed of the ball. Specifically, the rock's final speed is twice that of the ball's final speed because the time it falls is doubled, and since the acceleration due to gravity is constant, the final speed simply scales with time.
What type of pipe wrenches are designed for turning and holding where marring is not objectionable?
Final answer:
Mechanics extend the handle of a wrench with a pipe to increase leverage and torque, making it easier to remove very tight bolts, based on the physics principle of the lever arm. While effective, this increases the risk of over-torquing and potentially damaging equipment or injuring oneself.
Explanation:
When mechanics need to remove a very tight bolt, they may use a tactic that involves sliding a length of pipe over the handle of a wrench. This technique provides additional leverage which increases the torque applied to the bolt, making it easier to loosen. The physics principle at play here is that of the lever arm, where a longer handle effectively increases the distance from the pivot point (the bolt in this case), requiring less force to achieve the same amount of turning force or torque.
However, this increased torque also brings with it risks; applying too much force can shear or snap a bolt, potentially leading to equipment damage or personal injury. Therefore, while extending the handle of a wrench can be helpful, it is important to use this method with caution to avoid over-torquing.
Why Pipes over Wrench Handles Work
The principle behind using a pipe over a wrench handle is simple: a longer handle means you have a larger radius to apply your force, which translates to more torque on the bolt or nut.
During a test crash an airbag inflates to stop a dummy's forward motion. the dummy's mass is 75kg. If the net force on the dummy is 825n toward the rear of the car , what is the dummy's deceleration.
Using Newton's second law of motion, we find that the dummy's deceleration, given a net force of 825N and a mass of 75kg, is -11 m/s².
Explanation:To calculate the dummy's deceleration, we would make use of Newton's second law of motion, which states that the acceleration of an object as produced by a net force is directly proportional to the net force and inversely proportional to the mass of the object (F = ma).
In this scenario, the net force (F) is 825N (towards the rear of the car it would be considered negative), and the mass (m) of the dummy is 75kg. We can rearrange the equation to solve for acceleration (a), by dividing both sides by mass (m), giving us: a = F/m.
So, the dummy's deceleration (which is negative acceleration) would be -825N/75kg = -11 m/s². Therefore, the dummy's deceleration is -11 m/s².
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What is the force on a box that is being pushed to the right with 50n of force while, at the same time, being pushed to the left with a 20n force?
how does scientific knowledge develop through making observations about the natural world ?
Which type of force is found between difluorine (F2) molecules?
Answer:
London dispersion forces.
Explanation:
London dispersion forces, are the weakest type of intermolecular interactions. Its name is due to the contributions of the physicist Fritz London.
London forces explain how molecules whose structures and atoms prevent the formation of a permanent dipole. It basically applies to apolar molecules or to atoms isolated from noble gases.
Fluorine is a gas at room temperature, pale yellow in color, made up of F2 diatomic molecules. London forces are present in this gas since it has a homogeneous electrostatic distribution, which can suffer instantaneous dipoles and lead to polarizations.
When electrons in an atom in an excited state fall to lower energy levels, energy is?
Answer:
It gets released
Explanation:
a neutron. When electrons in an atom in an excited state fall to lower energy levels, energy is. released, only. (The ground state is the lowest energy state. To raise the atom to an excited state, energy must be added. To fall back to the ground state (lowest energy), the energy it had absorbed must be released.)
If millikan was measuring the charge on an oil droplet with 3 negatively charged electrons on it, what charge would he have measured on the droplet?
Millikan would have measured a charge of 4.8 imes [tex]10^{-19}[/tex] C on an oil droplet carrying 3 electrons, as each electron has a charge of 1.6 imes [tex]10^{-19}[/tex] C.
If Millikan was measuring the charge on an oil droplet with 3 negatively charged electrons on it, he would have measured a charge on the droplet by multiplying the charge of a single electron by the number of electrons on the droplet. Therefore, the charge measured would be 3 times 1.6 imes [tex]10^{-19}[/tex] C, which equals 4.8 imes [tex]10^{-19}[/tex] C. Each electron has a fundamental charge of 1.6 imes [tex]10^{-19}[/tex] C, a value that Millikan determined through his experiment to be the standard charge of a single electron.
Which characteristic is not a characteristic of plastic?
the diagram shows a vertical number line. what is the position of point X?
As per the question the diagram given is a vertical line.
We are asked to calculate the position of X.
Here the vertical line is divided into many segments.
As per the diagram, it is obvious that the points marked at different positions are separated by four units from each other i.e the distance between two successive marks is 4 units.
The point X is situated at four marks away from 0.
Hence the position of X will be= 4×4 units
= 16 units
Hence the correct answer of this question is D.
The correct answer is option 4, 16.
Explanation
Each division on the number line represents 4 units. The point X is located 4 divisions above 0, the origin. On this particular number line, 4 divisions represents [tex]4\times 4=16[/tex] units. This means that the point X is located at [tex]y=16[/tex] on the number line.
The correct answer is the 4th option, whose value is 16.
If your front lawn is 18.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1050 new snow flakes every minute, how much snow (in kilograms) accumulates on your lawn per hour? assume an average snow flake has a mass of 2.00 mg
Water is boiling in a clear pot, as shown in the picture. How do the water molecules closest to the burner compare to the water molecules closest to the surface of the liquid? They are more spread out and moving faster than those at the surface. They are closer together and moving faster than those at the surface. They are more spread out and moving slower than those at the surface. They are closer together and moving slower than those at the surface.
Answer:
they are more spread out and moving faster than those at the surface
Explanation:
fast easy and you don't have to read a whole book for the answer
Final answer:
Water molecules closest to the burner are more spread out and moving faster due to increased kinetic energy that leads water to transition from liquid to gas at the boiling point. This contrasts with the surface molecules that move less rapidly.
Explanation:
When boiling occurs in water, as the water molecules closest to the burner receive heat, they gain energy and move faster than the molecules at the surface. In this energized state, the molecules start moving more rapidly and become more spread out because the heat imparts kinetic energy to them, which is necessary to overcome the attractive forces between the water molecules. This increase in kinetic energy is what leads water to transition from the liquid phase to the gas phase at the boiling point.
Therefore, the water molecules closest to the burner are more spread out and moving faster than those at the surface of the liquid. Since the water at the boiling point has the water molecules throughout it gaining sufficient kinetic energy to vaporize, this agitation results in the formation of bubbles, which is a hallmark of the boiling process. At the surface, however, the evaporation is occurring at a lower rate than the boiling within the bulk of the liquid. Consequently, the surface molecules are not moving as rapidly as those at the bottom near the burner.
Light from the sun reaches earth in 8.3 min. how far is the earth from the sun? the velocity of light is 3 Ã 108 m/s. answer in units of m.
Light is a form of electromagnetic radiation that is visible to the human eye. The Earth is approximately 1.98 × 10¹¹ meters (198 million kilometers) away from the Sun.
Light is a type of energy that travels in the form of waves or particles called photons. Light is a fundamental component of our everyday lives and plays a crucial role in how we perceive and interact with the world around us.
Light is composed of different wavelengths, which determine its color. The visible spectrum of light ranges from shorter wavelengths, such as violet and blue, to longer wavelengths, such as green, yellow, orange, and red. When all these colors are combined, they form white light.
To determine the distance between the Earth and the Sun, we can use the formula:
Distance = Velocity × Time
Given that the velocity of light is 3 × 10⁸ m/s and the time taken for light to reach Earth is 8.3 minutes (or 8.3 × 60 seconds), we can substitute these values into the formula:
[tex]Distance = (3 * 10^8 m/s) * (8.3 * 60 s)[/tex]
Calculating the equation:
Distance = 1.98 × 10¹¹ meters
Therefore, the Earth is approximately 1.98 × 10¹¹ meters (198 million kilometers) away from the Sun.
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What is the name of the scientist who discovered that atoms have positive charges? A. John Dalton B. Robert Millikan C. Eugen Goldstein D. Ernest Rutherford
Discuss the validity of extrapolating the acceleration value to an angle of 90°.
Answer:
Yes, it is validated to extrapolate the acceleration value to an angle of 90 degrees.
Explanation:
Assume the friction-less inclined plane. There exists a mathematical relationship between angle of incline and the object rolling in downward direction on friction-less inclined plan.
Acceleration of object = sinθ × g
Here, θ=90 degrees so,
Acceleration of object = g = 9.8 m/s^2
Hence, it is validated to extrapolate the acceleration value to an angle of 90 degrees .
A stalled car is being pushed up a hill at constant velocity by three people. the net force on the car is
The net force on a car being pushed up a hill at constant velocity is zero because the forces pushing the car uphill exactly balance the forces pulling it downhill, as per Newton's first law.
When a stalled car is pushed up a hill at constant velocity by three people, according to Newton's first law, the net force acting on the car must be zero. This is because if an object is moving at a constant velocity, there is no acceleration, which implies that the sum of all forces acting on the object is zero. In this case, the forces involved include the force of gravity acting downward on the car (its weight), the normal force acting perpendicular to the surface of the hill, the force of friction opposing the motion, and the pushing force by the people. Each of these forces has a vertical and horizontal component that must be considered.
For the car to have a net force of zero, the forces pushing the car up the hill must exactly balance out the forces such as gravity and friction that oppose this motion. Specifically, the uphill pushing force (from the people) plus any component of the normal force, must balance out the downhill force of gravity and any frictional force. Since the question states the car is moving at constant velocity, we can conclude that the forces are balanced, and therefore, the net force on the car is zero.
Neglecting air resistance, what maximum height will be reached by an arrow launched straight upward with an initial speed of 35 m/s
The maximum height reached by the arrow launched straight upward with an initial speed of 35 m/s is 62.5 meters.
Explanation:To calculate the maximum height reached by an arrow launched straight upward, we can use the equations of motion. Neglecting air resistance, the arrow will reach its maximum height when its vertical velocity becomes zero. The equation to calculate the maximum height, h, is given by:
h = (v2) / (2g)
where v is the initial speed of the arrow and g is the acceleration due to gravity.
Plugging in the values, we get:
h = (352) / (2 * 9.8) = 62.5 meters
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A car travelling 95 km/h is 210 behind a truck travelling 75 km/h. how long will it take the care to reach the truck
Strenuous activity releases a substance called _________________into your bloodstream. Question 4 options: Nutrients Blood Lactic Acid Oxygen
Ou are walking around your neighborhood and you see a child on top of a roof of a building kick a soccer ball. the soccer ball is kicked at 47° from the edge of the building with an initial velocity of 21 m/s and lands 57 meters away from the wall. how tall is the building that the child is standing on?