I don’t understand this pls help

On a level track with little friction, two identical freight cars roll toward each other. The collision causes the two freight cars to move together at a velocity of 1.5 m/s.

Conservation of momentum applies in this situation, as there are no external forces acting on the system. The momentum of the system before the collision is:

Pinitial = m₁v₁ + m₂v₂

where m₁ and m₂ are the masses of the freight cars, and v₁ and v₂ are their velocities before the collision.

Since the two freight cars are identical, their masses are equal, so we can write:

Pinitial = 2m × 2 m/s + 2m × 1 m/s = 6m kg m/s

where 2m is the mass of each freight car.

After the collision, the two freight cars move together as one unit, with a common velocity v. The final momentum of the system is:

Pfinal = (2m + 2m) × v = 4m × v

According to the law of conservation of momentum, the initial momentum of the system must equal the final momentum of the system. Therefore:

Pinitial = Pfinal

6m kg m/s = 4m × v

Solving for v, we get:

v = 1.5 m/s

So after the collision, the two freight cars move together with a velocity of 1.5 m/s.

Friction is a force that opposes motion between two surfaces in contact, caused by the irregularities in their surfaces.

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Answer:

000.83

Explanation:

i dont know how to explain it bt i did something on paper for it

The refraction of a sound wave occurs when the sound wave bends as it passes through the boundary between media. Refraction occurs when there is a difference in the speed of sound waves in two different media.

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Answer:

yes they do

Explanation:

Answer:

The graph is the answer to the question.

Explanation:

The rocket launches straight up, and the acceleration is constant.

The Complete Question is added below

c) Velocity of the of the rocket after the first 10sec of travel is

   \(v=50m/s\)

From the Question we are told that

Upward acceleration of 5 m/s^2 for 10 seconds

Rocket freely falls straight down back to Earth's surface

Generally the Newtons equation for Velocity  is mathematically given as

  \(v=u+at\\\\v=(0)+(5)(10)\)

  \(v=50m/s\)

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Answer:

4.4 min

Explanation:

To solve this, we use the law of conservation of momentum

0 = -m(a).v(a) + m(c).v(c), where

m(a) = mass of the astronaut

m(c) = mass of the camera

v(a) = velocity of the astronaut

v(c) = velocity of the camera

Making v(a) subject of the formula, we have

v(a) = m(c).v(c)/m(a)

Now, we make one last assumption, that the astronaut is moving at constant speed and time, thus the time needed will be

t = s/v -> since s = vt

Now, we already have our v from above, so we substitute

t = s/[m(c).v(c)/m(a)]

t = s.m(a)/m(c).v(c)

Applying the values, we have

t = (41.4 * 70.1) / (0.916 * 12)

t = 2902.14 / 10.992

t = 264 seconds or 4.4 minutes

It's not 65 s, I can tell you that for sure

The statement that correctly describes a property of sound waves is that they require particles to transfer energy.

The correct option is D.

A sound wave is a pattern of disturbance that occurs as a result of the movement of energy moving through a medium as it propagates away from the source of the sound (such as air, water, or any other liquid or solid matter).

Pressure waves are produced when an object vibrates, such as a ringing phone, and these waves are known as sound waves.

Sound waves are mechanical waves and require a material medium for their propagation.

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Answer:

the required revolution per hour is 28.6849

Explanation:

Given the data in the question;

we know that the expression for the linear acceleration in terms of angular velocity is;

\(a_{c}\) = rω²

ω² = \(a_{c}\) / r

ω = √( \(a_{c}\) / r )

where r is the radius of the cylinder

ω is the angular velocity

given that; the centripetal acceleration equal to the acceleration of gravity a \(a_{c}\)  = g = 9.8 m/s²

so, given that, diameter = 4.86 miles = 4.86 × 1609 = 7819.74 m

Radius r = Diameter / 2 = 7819.74 m / 2 = 3909.87 m

so we substitute

ω = √( 9.8 m/s² / 3909.87 m )

ω = √0.002506477 s²  

ω = 0.0500647 ≈ 0.05 rad/s  

we know that; 1 rad/s = 9.5493 revolution per minute

ω = 0.05 × 9.5493 RPM

ω = 0.478082 RPM  

1 rpm = 60 rph  

so  

ω = 0.478082 × 60

ω = 28.6849  revolutions per hour  

Therefore, the required revolution per hour is 28.6849

The required revolution per hour is 28.6849

The expression for the linear acceleration with respect to the angular velocity is

= rω²

So,

ω² =  / r

ω = √(  / r )

Here r represent the radius of the cylinder

ω represent the angular velocity

Now

diameter = 4.86 miles = 4.86 × 1609 = 7819.74 m

And,

Radius r = Diameter / 2 = 7819.74 m / 2 = 3909.87 m

So,

ω = √( 9.8 m/s² / 3909.87 m )

ω = √0.002506477 s²  

ω = 0.0500647 ≈ 0.05 rad/s  

Now

1 rad/s = 9.5493 revolution per minute

So,

ω = 0.05 × 9.5493 RPM

ω = 0.478082 RPM  

Now

1 rpm = 60 rph  

so  

ω = 0.478082 × 60

ω = 28.6849  revolutions per hour  

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\(q = -21 * 10^{-6} C\)

The acceleration is constant and equal to the gravitational acceleration g which is 9.8 m/s at sea level on the Earth.

As we know that charge and its sign that remains in equilibrium is under gravity must be such that it will balance the gravitational force by electric force,

mg =qE

\(1.45 * 10^{-3}(9.80)=q(600)\\\\q = 21 *10^{6} C\\\\\)

and its sign must be negative so that it will have upward electric force

so it is

\(q = -21 * 10^{-6} C\)

The charge of a particle of mass is \(-21 * 10^{-6} C\)

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Answer:

Increases

Explanation:

The light is emerging from a denser medium to rarer medium so the average light speed increases.

When a light beam emerges from water into air, the average light speed increases.

      The bending of a ray passes at an angle from one medium to another in which the speed will be different, as when light passes from air into water and also from water into air can be known as refraction.

      When light travels from water to air, the angle from water to air the light  gets speeds up and then its changes direction. The light turns away from the normal line. Because the light moves from a denser medium to the rarer medium. But from air to water the speed will be decreased because in that case the light travels from the rarer medium to the denser medium.

Hence, the light beam when passes, the average speed gets increased.

So, Option A is the correct answer.

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Answer:

decreases, decreases

Explanation:

To calculate the torque required to create an angular acceleration, we can use the formula:

Torque = Moment of Inertia × Angular Acceleration

The moment of inertia of a disk can be calculated using the formula:

Moment of Inertia = (1/2) × Mass × Radius^2

Given:

Mass = 15,000 kg

Radius = 6.14 m

Angular Acceleration = 0.0500 rad/s^2

First, calculate the moment of inertia:

Moment of Inertia = (1/2) × Mass × Radius^2

Moment of Inertia = (1/2) × 15,000 kg × (6.14 m)^2

Next, calculate the torque:

Torque = Moment of Inertia × Angular Acceleration

Torque = Moment of Inertia × 0.0500 rad/s^2

Now, let's plug in the values and calculate:

Moment of Inertia = (1/2) × 15,000 kg × (6.14 m)^2

Moment of Inertia ≈ 283,594.13 kg·m^2

Torque = 283,594.13 kg·m^2 × 0.0500 rad/s^2

Torque ≈ 14,179.71 N·m

Rounding to three significant figures, the torque required to create an angular acceleration of 0.0500 rad/s^2 is approximately 14,180 N·m.

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Answer:

I think this is the answer

Explanation:

Answer:

The frequency of a string wave is 922.5 Hz

Explanation:

Given;

length of the string, L = 0.65 m

initial speed of the string wave at n = 5, v₁ = 320 m/s

initial frequency of the wave speed, f₁ = 1230 Hz

final speed of the string wave at n = 5, v₂ = 240.0 m/s

final  frequency of the wave speed, f₂ = ?

speed of wave is related to frequency of wave and wavelength by the following equation;

V = Fλ

If the wavelength is constant at n = 5, then

\(\lambda = \frac{V_1}{f_1} = \frac{V_2}{f_2}\\\\f_2 = \frac{f_1V_2}{V_1} \\\\f_2 =\frac{1230*240}{320} \\\\f_2 = 922.5 \ Hz\)

Therefore, the frequency of a string wave, if speed of 240.0 m/s is used is 922.5 Hz

Answer:

2¹/2

Explanation:

if the revolution is in 10 seconds the R,=Total time÷time of the revolution

Answer:

The object will make \(2\frac{1}{2}\)  (2.5) revolutions in 25s.

This indicates that it will revolve through two full revolutions before rotating a third time in the opposite direction.

Explanation:

A rotational period of 10 seconds indicates that an object completes one full rotation every 10 seconds. The object's frequency is therefore 1/10 Hz, or 0.1 Hz. We must apply the calculation to determine how many revolutions it will complete in 25 seconds:

Number of revolutions = frequency x time passed

We are informed that 25 seconds have passed. Using the following formula, we can determine the frequency:

Frequency = 1 / period.

The frequency is because the period is 10 seconds:

Frequency equals 1/10, or 0.1 Hz.

Now we can calculate the number of revolutions using the formula above:

Number of revolutions = (25 s) x (0.1 Hz) = 2.5 revolutions

It takes 10 seconds for the first complete revolution, another 10 seconds for the second full revolution, and 5 seconds for the final half revolution.

In other words, the object starts at its starting location, rotates a whole anticlockwise revolution, another full anticlockwise revolution, and then eventually rotates a further half anticlockwise revolution before returning to its initial position. As a result, the item in this instance rotates in the opposite direction of clockwise.

As a result, in 25 seconds, the object will complete 2.5 revolutions.

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(a) The work done by the 150 N force is 877.5 Joules.

(b) The coefficient of kinetic friction between the crate and the surface is approximately 0.437.

To answer this problem, we must take into account the work done by the applied force as well as the work done by friction.

(a) The applied force's work may be estimated using the following formula:

Work = Force * Distance * cos(theta)

where the force is 150 N and the distance is 5.85 m. Since the force is applied horizontally and the displacement is also horizontal, the angle theta between them is 0 degrees, and the cosine of 0 degrees is 1.

As a result, the applied force's work is:

Work = 150 N * 5.85 m * cos(0) = 877.5 J

So, the work done by the 150 N force is 877.5 Joules.

(b) Frictional work is equal to the force of friction multiplied by the distance. The work done by friction is identical in amount but opposite in direction to the work done by the applied force since the crate travels at a constant speed.

The frictional work may be estimated using the following formula:

Work = Force of Friction * Distance * cos(theta)

The net force applied on the crate is zero since it is travelling at a constant pace. As a result, the friction force must be equal to the applied force, which is 150 N.

Thus, the work done by friction is:

Work = 150 N * 5.85 m * cos(180) = -877.5 J

Since the work done by friction is negative, it indicates that the direction of the frictional force is opposite to the direction of motion.

The coefficient of kinetic friction may be calculated using the following equation:

Friction Force = Kinetic Friction Coefficient * Normal Force

The normal force equals the crate's weight, which may be computed as:

Normal Force = mass * gravity

where the mass is 35.0 kg and the acceleration due to gravity is approximately 9.8 m/s^2.

Normal Force = 35.0 kg * 9.8 m/s^2 = 343 N

Now, we can rearrange the equation for the force of friction to solve for the coefficient of kinetic friction:

Force of Friction = coefficient of kinetic friction * Normal Force

150 N = coefficient of kinetic friction * 343 N

coefficient of kinetic friction = 150 N / 343 N ≈ 0.437

As a result, the kinetic friction coefficient between the container and the surface is roughly 0.437.

In summary, the work done by the 150 N force is 877.5 Joules, and the coefficient of kinetic friction between the crate and the surface is approximately 0.437.

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The field strength can be calculated by using the equation B = mv/qr, where B is the magnetic field strength, m is the mass of the proton, v is the velocity of the proton, q is the charge of the proton, and r is the radius of the circular path.

In this case, the field strength is equal to 3.34 x 10-13 T.

The magnetic influence on moving electric charges, electric currents, and magnetic materials is described by a magnetic field, which is a vector field. A force perpendicular to the charge's own velocity and the magnetic field acts on it when the charge is travelling through a magnetic field.

Iron fillings can be utilized to reveal this field, which is invisible to the human eye. The north pole and the south pole are the two endpoints of every magnet. Magnetic objects are either drawn to or pushed away by magnetism. When two magnets with the same poles are placed close to one another, they push apart and repel.

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Answer:

a) the acceleration of the particle is (  v\(_f\)² - v\(_i\)² ) / 2as

b) the integral W = \(\frac{1}{2}\)m( \(_f\)² - v\(_i\)² )

Explanation:

Given the data in the question;

force on particle F = ma

displacement s = x\(_f\) - x\(_i\)

work done on the particle W = Fs = mas

we know that; change in energy = work done       { work energy theorem }

\(\frac{1}{2}\)m(  v\(_f\)² - v\(_i\)² ) = mas

\(\frac{1}{2}\)(  v\(_f\)² - v\(_i\)² ) = as

(  v\(_f\)² - v\(_i\)² ) = 2as

a = (  v\(_f\)² - v\(_i\)² ) / 2as

Therefore, the acceleration of the particle is (  v\(_f\)² - v\(_i\)² ) / 2as

b) Evaluate the integral W = \(\int\limits^{v_{f} }_{v_{i} } mvdv\)

\(W = \int\limits^{v_{f} }_{v_{i} } mvdv\)

\(W =m[\frac{v^{2} }{2} ]^{vf}_{vi}\)

W = \(\frac{1}{2}\)m( \(_f\)² - v\(_i\)² )

Therefore, the integral W = \(\frac{1}{2}\)m( \(_f\)² - v\(_i\)² )

Answer:

Object, starting from rest, will fall at 137.34m/s after 14s.

Explanation:

Assuming that the object falls from rest (ie it's dropped, not thrown), initial velocity, u, is equal to 0m/s.

Assuming this object is falling on earth, the acceleration it undergoes due to gravity, a, is equal to 9.81m/s².

We are looking for v, the final speed at t=14s.

v=u+at

=0+(9.81)(14)

=137.34m/s

ANSWER

c. 309°C

EXPLANATION

The average kinetic energy of the molecules in an ideal gas is proportional to the temperature of the gas,

Where the temperature is measured in Kelvin.

For this problem it is not necessary to specify what is the value of k, we just need to know that it is a constant.

So, if the kinetic energy doubles, so does the temperature (in Kelvin).

The initial temperature of the gas is,

If the temperature doubles,

In degrees Celsius this is,

Hence, the final temperature of the gas is 309°C.

Answer:

kinetic energy = 0.1168 J

Explanation:

From Hooke's law, we know that ;

F = kx

k = F/x

We are given ;

Mass; m = 1.95 kg

Spring stretch; d = x = 0.0865

So, Force = mg = 1.95 × 9.81

k = 1.95 × 9.81/0.0865 = 221.15 N/m

Now, initial energy is;

E1 = mgL + ½k(x - L)²

Also, final energy; E2 = ½kx² + ½mv²

From conservation of energy, E1 = E2

Thus;

mgL + ½k(x - L)² = ½kx² + ½mv²

Making the kinetic energy ½mv² the subject, we have;

½mv² = mgL + ½k(x - L)² - ½kx²

We are given L=0.0325 m

Plugging other relevant values, we have ;

½mv² = (1.95 × 9.81 × 0.0325) + (½ × 221.15(0.0865 - 0.0325)² - ½(221.15 × 0.0865²)

½mv² = 0.62170875 + 0.3224367 - 0.82734979375

½mv² = 0.1168 J

Answer:

be in front of the club

Explanation:

The ball should be highest off the ground for a driver. The general recommendation is that the bottom of the golf ball on a tee should be level with the top of the driver; for long and mid-irons, push the tee into the ground so that only about a quarter-inch is above ground.

The earthquake would occur 13 minutes before 10:05 a.m. which will be at 9.52 am.

The p-waves travel with a constant velocity of 7 km/s

The time can be calculated by using the formula

t = d / v

where

T1 =  10:05 a.m

d is the distance they take to travel from the epicenter

v is the speed of the p-waves

On average, the speed of p-waves is

v = 7 km/s

d = 5600 km (given)

Substituting the values in the formula;

t = d / v

t = 5600 ÷ 7

t = 800 seconds

Converting into minutes,

t = 800 ÷ 60

t = 13.3

≈ 13 mins

T1 -  13 mins = T2

10:05 - 13 mins = 9.52 am

It means the earthquake occurred prior 13 minutes, that is at 9.52 am.

Therefore, the earthquake occurred at 9.52 am.

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Using the conversion factor that we have seen in the solution, the value obtained is 40.25 kilometers per hours

To convert miles per hour (mph) to kilometers per hour (kph), you need to multiply the speed value in mph by a conversion factor of 1.61, which is the number of kilometers in one mile.

Given that;

1 miles/hour = 1.61 kilometer per hour

25 miles per hour = 25 * 1.61/1

= 40.25 kilometers per hours

Hence the value that we get is 40.25 kilometers per hours

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The convert unit of  25 miles per hour is equivalent to 40.2335 kilometers per hour

Unit conversion is the process of converting a value expressed in one unit of measurement to another unit of measurement that is equivalent in terms of its value or quantity. This is done by using a conversion factor, which is a numerical factor that relates the two units of measurement.

To convert miles per hour (mph) to kilometers per hour (km/h), we need to multiply the speed in mph by 1.60934, which is the conversion factor from miles to kilometers.

So, to convert 25 mph to km/h:

25 mph × 1.60934 = 40.2335 km/h

Therefore, 25 miles per hour is equivalent to 40.2335 kilometers per hour.

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Answer:

h = 157.70 meters

Explanation:

Given the following data;

Mass = 5.5 kg

Gravitational potential energy = 8500 Joules

We know that acceleration due to gravity is equal to 9.8 m/s².

To find the height of the object;

Gravitational potential energy (GPE) is an energy possessed by an object or body due to its position above the earth.

Mathematically, gravitational potential energy is given by the formula;

\( G.P.E = mgh\)

Where;

G.P.E represents potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per seconds square.

h represents the height measured in meters.

Substituting into the formula, we have;

8500 = 5.5*9.8*h

8500 = 53.9h

h = 8500/53.9

h = 157.70 m

ANSWER

R2 = 2R1

The range of the second projectile is two times the range of the first projectile.

EXPLANATION

The gun is always in the same position and two projetiles are fired at different speeds:

Because the gun is in the same position above the floor and for both projectiles the initial vertical speed is 0 both projectiles are in the air the same time t.

The range for each projectile is

And we know that the speed of the second projectile is twice the speed of the first projectile:

Replace this into the equation of the range of the second projectile

And note that next to the 2 coefficient there's the equation for the range of projectile 1:

Therefore the range of the second projectile is two times the range of the first projectile.

The primary means by which heat is transferred through fluids is convection currents (option D).

Convection is the transmission of heat in a fluid by the circulation of currents.

Heat can be transferred by different methods depending on the medium. Fluids like gases and liquids transfer heat through the process of convection.

Therefore, the primary means by which heat is transferred through fluids is convection currents.

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With the use of first and third equation of motion, the distance covered by a T-Rex is 30.51 m

When a body is in linear motion, the body is moving in a straight line. some of the parameters to consider are:

Given that a T-Rex move from 0 m/s to 9 m/s in 6.78 seconds, the distance covered can be found by calculating the acceleration.

Let us use equation 1

V = U + at

9 = 0 + 6.78a

a = 9 / 6.78

a = 1.33 m/\(s^{2}\)

Now let us use equation 3

\(v^{2}\) = \(u^{2}\) + 2as

\(9^{2}\) = 2 x 1.33 x S

81 = 2.655S

S = 81/2.655

S = 30.51 m

Therefore, the distance covered by a T-Rex is 30.51 m.

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Answer:

Some liquids flow really fast and some flow really slow.

Explanation:

This is because of a liquids viscosity , If the liquids viscosity is high it will flow really slow like syrup. But if it has high viscosity it will flow really fast much like water.

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