which of the following correctly describes a longitudinal wave

Statement a and e are in static equilibrium, b and d are in dynamic equilibrium and c is not at equilibrium at all.

When the net force acting on an object is zero, the object is said to be at equilibrium. The state of equilibrium can be classified into two: static and dynamic.

Static equilibrium is when the net force is zero resulting in the object being at rest or not moving.

Dynamic equilibrium is when the resultant force acting on an object is zero and the object is moving in a uniform motion (i.e. constant or unchanging speed).

A. a 200 pound barbell is held above your head

Since the barbel is "held above your head" and is implied to be at rest since there is no change in its position during the time it is held, then this situation is an example of static equilibrium.

B. A girder is being lifted at a constant speed by a crane

This is dynamic equilibrium because the object is moving "at a constant speed".

C. A girder is being lowered into place. It is slowing down.

This is not equilibrium condition because the objects is neither at rest nor moving at a constant speed. It is "slowing down", so the speed is decreasing.

D. A jet plane has reached its cruising speed and altitude.

The "cruising speed" is the speed that is maintained while the jet plane is traveling because this is considered to be the most efficient speed. Since it is maintained, the jet plane is said to be in constant motion. Therefore, this is dynamic equilibrium.

E. A box in the back of a truck doesn't slide as the truck stops.

This is static equilibrium because the box is stationary or not moving.

Keywords: equilibrium, static equilibrium, dynamic equilibrium

Objects in static equilibrium are at rest with balanced forces, while those in dynamic equilibrium move with constant velocity and no acceleration. A barbell held still is in static equilibrium, a girder moving consistently while being lifted is in dynamic equilibrium, and a plane at cruising altitude and speed is also in dynamic equilibrium.

Objects can be in either static equilibrium, dynamic equilibrium, or not in equilibrium at all. When an object is at rest and the net external force and torque acting on it are zero, it is in static equilibrium. On the other hand, an object in motion with constant velocity and zero acceleration, where the net external forces and torques are also zero, is in dynamic equilibrium.

Zero acceleration means that the object's velocity is constant, not that it is zero. An object in motion could have zero acceleration if it's moving at a consistent speed in a straight line. An object at rest would have both zero acceleration and zero velocity.

Even if an object has zero acceleration, that does not necessarily mean it has zero velocity. In Physics, velocity is the speed of an object in a particular direction, and acceleration is the rate at which its velocity changes. If an object's acceleration is zero, that means the object's velocity is not increasing or decreasing—it's constant. For example, an object moving at a consistent speed of 10 m/s in a straight line would have zero acceleration. However, its velocity is not zero because it is still moving. On the other hand, an object at rest would also have zero acceleration and zero velocity. Therefore, zero acceleration indicates constant velocity but the velocity could be any value, including zero.

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If you're going really really slow and you hit the brakes, you're going to stop almost instantly. When you're going faster, you've got your energy which is your body size so it takes energy to stop the bike. When you slam the brake you're trying to apply that energy to the wheels. Even if you lock them up so the wheels aren't spinning, you skid because friction is rubbing against the ground and that will be what eventually stops you.

If you have a wider tire, you're going to have more surface area hitting the ground and that will cause more friction so you will stop faster. If you have skinnier tires you will skid more so there are a bunch of different factors.

The torque exerted by the mouse's weight on the clock's minute hand is calculated to be 0.09163 N·m using the torque formula with force, radius, and the angle between them.

To determine the torque exerted by the mouse's weight on the clock's minute hand when it is 10 minutes past the hour, we need to apply the formula:

Torque (τ) = r × F × sin(θ)

Here:

Substituting these values into the formula:

τ = 0.17 m × 0.539 N × 1 = 0.09163 N·m.

Thus, the torque exerted by the mouse's weight about the rotation axis of the clock hand is 0.09163 N·m.

Answer: deflate because volume is directly proportional to temperature

Explanation:

Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

[tex]V\propto T[/tex]     (At constant pressure and number of moles)

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

where,

[tex]V_1[/tex] = initial volume of gas

[tex]V_2[/tex] = final volume of gas

[tex]T_1[/tex] = initial temperature of gas

[tex]T_2[/tex] = final temperature of gas

As volume is directly proportional to temperature, as the balloon is kept in freezer, the temperature would decrease and thus the volume will decrease and it will deflate.

The density of gold is 19.3 grams per cubic centimeter. To convert this to metric tons per cubic meter, we convert grams to metric tons and cubic centimeters to cubic meters, which gives us a density of 19.3 metric tons per cubic meter.

The question asks for the density of gold in metric tons per cubic meter. Gold's known density is 19.3 grams per cubic centimeter. To convert this to metric tons per cubic meter, we first need to convert grams to metric tons. We know that 1 metric ton equals 1,000,000 grams. Therefore, 19.3 grams is 0.0000193 metric tons. Then, we need to convert cubic centimeters to cubic meters. As there are 1,000,000 cubic centimeters in a cubic meter, the density of gold becomes: 0.0000193 metric tons times 1,000,000, equaling 19.3 metric tons per cubic meter.

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Answer:

The relative speed of the boat is found to be - 2 m/s or 2 m/s in opposite direction to the river current.

Explanation:

Let us, consider the direction of river as the reference of positive direction. Hence,

Speed of River = Vr = 8 m/s

Since, the boat is traveling upstream. The upstream direction means that the boat is traveling in the opposite direction of the river current. Therefore, its direction will be negative. Hence,

Speed of boat = Vb = - 10 m/s

Now, the relative speed will be the vector sum of both speeds, with relative directions:

Relative Speed = V = Vr + Vb

V = 8 m/s - 10 m/s

V = - 2 m/s

This shows that the magnitude of speed of boat is 2 m/s and its direction will be opposite to that of river current.

To find the boat's speed relative to the riverbank, subtract the river current's speed from the boat's speed. The resulting speed is 2.0 m/s upstream relative to the riverbank.

Calculating the Boat's Speed Relative to the Riverbank

To determine the boat’s speed relative to the riverbank, we need to consider both its own speed and the speed of the river current.

When traveling upstream, the boat’s speed relative to the riverbank can be found by subtracting the speed of the river current from the boat’s speed:

[tex]\text{Relative speed = Speed of the boat - Speed of the river current}[/tex]

Therefore,

[tex]\text{Relative speed} = 10.0 m/s - 8.0 m/s = 2.0 m/s.[/tex]

Thus, the boat is moving at 2.0 m/s relative to the riverbank when it is traveling upstream.

Answer:

Correlations allow you to determine causes.

Explanation:

I just had this on my lesson and used the other answer and I got it wrong so I just wanted to make it correct!! (FYI i saw the right answer on my lesson after I got it wrong)

Final answer:

The correct answer is that if we decrease the voltage without changing the resistance, the current will decrease. So, the correct option is B.

Explanation:

The statement that correctly describes the relationship between current, voltage, and resistance is: If we decrease the voltage, and do not change the resistance, the current will also decrease. This is in accordance with Ohm's Law which states that current (I) is equal to the voltage (V) divided by the resistance (R), or I = V/R. Therefore, if the voltage is decreased and resistance remains constant, the current will decrease as well.

Regarding the parallel circuit question, if two identical resistors are connected in parallel and the resistance of one is increased, the current through the unaffected resistor remains the same because the voltage across it hasn't changed. However, the total current in the circuit will decrease because the overall resistance has increased.

To increase the power dissipated in a circuit with constant current, one should reduce the resistance. Power (P) can be calculated using the formula P = I2R, where I is current and R is resistance. Reducing resistance increases power dissipation.

Answer:

Duck's kinetic energy is 64.8 Joules

Explanation:

It is given that,

Mass of the duck, m = 0.9 kg

Velocity of the duck is, v = 12 m/s

We have to find the velocity of the duck. It is given due to the motion of an object. Mathematically, it is written as :

[tex]KE=\dfrac{1}{2}mv^2[/tex]

[tex]KE=\dfrac{1}{2}\times 0.9\ kg\times (12\ m/s)^2[/tex]

KE = 64.8 Joules

Hence, the kinetic energy of the duck is 64.8 Joules              

Answer:

[tex]6.3\times10^3 km[/tex]

Explanation:

First, convert meters to kilometers:

[tex]6370000m*\frac{1km}{1000m} =6370km[/tex]

Now, express it using scientific notation following the next steps:

Therefore:

[tex]6370km=6.3\times 10^3km[/tex]

The radius of the Earth in scientific notation with the correct number of significant digits is 6.37 × [tex]10^6[/tex] km

To express the radius of the Earth in scientific notation with the correct number of significant digits, we need to count the number of significant digits in the original measurement and then convert it to scientific notation.

The original measurement is 6,370,000 meters.

Step 1: Count the significant digits:

There are four significant digits in the number 6,370,000.

Step 2: Convert to scientific notation:

To express the number in scientific notation, we move the decimal point to the position where we have only one non-zero digit before the decimal point. In this case, that's the number 6. To do that, we need to move the decimal point six places to the left:

6,370,000 = 6.37  × [tex]10^6[/tex]

Step 3: Add the correct number of significant digits:

Since there were four significant digits in the original number, we need to keep four significant digits in the scientific notation as well.

Therefore, the radius of the Earth in scientific notation with the correct number of significant digits is:

6.37  × [tex]10^6[/tex] km

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Answer:  10.3

Explanation:  Edge

Vector is a quantity that has a magnitude and direction.

A vector in a cartesian coordinate is represented by an arrow in which the slope of the arrow shows the direction of the vector and the length of the arrow shows the magnitude of the vector.

A position vector of a point is a vector drawn from the base point of the coordinates O (0,0) to that point.

The addition of two vectors can be done in the following ways:

[tex]\overrightarrow {AB} + \overrightarrow {BC} = \overrightarrow {AC}[/tex]

A negative vector is a vector with the same magnitude but in opposite direction.

[tex]\overrightarrow {AB} = -\overrightarrow {BA}[/tex]

Let's tackle the problem!

Two vectors are equal if they have the same magnitude and direction. In the attached picture, it can be clearly seen that the vector AB has the same magnitude and direction with vector DC. Therefore, vector AB is equal to vector DC.

Grade: High School

Subject: Physics

Chapter: Vectors

Keywords: Velocity , Driver , Car , Deceleration , Acceleration , Obstacle , Speed , Time , Rate , Vector , Scalar

The vector r⃗ AB denotes the vector from point A to point B. It is calculated by subtracting the coordinates of point A from the coordinates of point B. To determine which of the presented vectors corresponds to r⃗ AB, knowledge of the coordinates of points A and B is required.

The vector r⃗ AB represents the vector from point A to point B. In order to identify which of the given vectors is equal to r⃗ AB, you would need to know the coordinates of points A and B. The vector r⃗ AB is computed by subtracting the coordinates of point A from the coordinates of point B (i.e., B - A). For example, if point A has coordinates (x1, y1) and point B has coordinates (x2, y2), then the vector r⃗ AB would be (x2-x1, y2-y1).

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Explanation :

Given that,

Mass of the spaceship 1, m = 300 kg

Initial momentum of the spaceship 1, p = 600 kgm/s

Momentum is the product of the mass and the velocity with which it is moving i.e.

p = m v

[tex]v=\dfrac{p}{m}[/tex]

[tex]v=\dfrac{600\ kgm/s}{300\ kg}[/tex]

[tex]v=2\ m/s[/tex]

The initial velocity of the spaceship 1 is 2 m/s.

Hence, this is the required solution.

Final answer:

To find the initial speed of spaceship 1 with a momentum of 600 kg-m/s and mass of 300 kg, one should use the momentum formula (momentum = mass * velocity) and solve for velocity, resulting in an initial speed of 2 m/s.

Explanation:

To calculate the initial speed of spaceship 1 with a given momentum, we need the formula for momentum, which is the product of mass and velocity (p = m * v). Since we have the mass (m = 300 kg) and the momentum (p = 600 kg-m/s), we can solve for the initial speed (v) of spaceship 1 by rearranging the formula to v = p / m.

Doing the calculation gives us v = 600 kg-m/s / 300 kg, which results in v = 2 m/s. Therefore, the initial speed of spaceship 1 is 2 meters per second.

The three hallmarks of science are empiricism, skepticism, and the use of rational arguments.

The three hallmarks of science are: empiricism, skepticism, and the use of rational arguments. Empiricism refers to the concept that all knowledge is derived from sensory experience. It involves the collection of data and observation of phenomena. Skepticism in science refers to the practice of questioning the validity and reliability of claims and not accepting them blindly. It involves requiring substantial evidence before affirming a claim. Rational arguments refer to using logical reasoning to explain natural events. Scientists use rational arguments to construct theories from experimental results.

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The density of the block is 8.9 gm/cm³

What is volume ?

Volume is a three dimensional space occupy by the body of particular shape. Generally expressed in cubic meter.

Here, it is given that length of block (l) = 2 cm

breadth of block (b) = 4 cm

heigth of block (h) = 5 cm

weight of block (m) = 356 gm

the volume of the block is calculated using formula :

[tex]\begin{aligned}V&= lbh\\&=2\cdot4\cdot5\\&=40 \text{ cm}^{3}\end{aligned}[/tex]

Now density of block will  be :

[tex]\begin{aligned}\rho&=\frac{m}{V}\\&=\frac{356}{40}\\&=8.9 \:\text{gm}/ \text{cm}^{3}\end{aligned}[/tex]

Therefore, the density of the block is 8.9 gm/cm³

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Answer:

If an atom of nitrogen binds wit three hydrogen atoms to form a molecule of ammonia, the nitrogen have one lone pairs of electrons.

Explanation:

Ammonia is the binding of nitrogen to three hydrogens covalently, that is, the bonds that form share their electrons to acquire the stability of the electronic structure of the noble gas. Shared electrons are located at the outermost level (valence electrons).  

Nitrogen has five pairs of electrons in its valence layer, wishing to have eight electrons to acquire stability. Hydrogen has an electron in its outer shell, and it must have two electrons to be stable. If nitrogen shares an electron covalently with each of the three hydrogens, the latter will have the two electrons to complete its outer shell and be stable. And nitrogen will acquire the three necessary electrons, one for each hydrogen bond, to have eight electrons and acquire stability. But, as mentioned, the nitrogen in its outer shell has five electrons. If three of them are shared covalently, there is a pair of electrons that is not shared.  These two electrons, which form the pair of electrons, is the solitary pair or pair of electrons that are not shared, that is, the pair of valence electrons that is not forming a bond, nor shared with other atoms. This is what causes the ammonia molecule not to have a flat shape, but to have a tetrahedral shape.

So, if an atom of nitrogen binds wit three hydrogen atoms to form a molecule of ammonia, the nitrogen have one lone pairs of electrons.

Answer:

Part a)

Distance = 28.5 cm

Part b)

Displacement = 15.5 cm

Explanation:

Part a)

Total distance moved by the ball is given as total path length

so here we can say

distance moved in positive direction = 22 cm

distance moved in negative direction = 6.5 cm

total path length = 22 + 6.5 = 28.5 cm

Part b)

Displacement is the shortest distance between initial and final position

so we need to add vectorially

so here we have

displacement in positive direction = 22 cm

displacement in negative direction = 6.5 cm

Total displacement = 22 - 6.5 = 15.5 cm