Does sound travel faster or slower when the air gets warmer?

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.

Answer: A: based in scientific evidence.

Explanation:

Scientific laws are made after proper research under varying conditions using scientific method to show that a particular theory is right under stated conditions

Scientific laws are carried out using methods ands not just any process with condition taken into consideration

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.

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.

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:

For the rock that falls for 4 seconds:

Thus, 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.

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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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.)

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.

The above statement is true

Swinging a tennis racket against a ball is an example of a third class lever.

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 .

The maximum height reached by the arrow launched straight upward with an initial speed of 35 m/s is 62.5 meters.

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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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.

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.

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.

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: