A train crosses a platform 100 m long in 60 sec at a speed of 45 kmph. Find the time taken by the train to cross an electric pole.
How do you handle this type of question and also how do you find the length of the train? A train crosses a platform 100 m long in 60 sec at a speed of 45 kmph. Find the time taken by the train to cross an electric pole.
How do you handle this type of question and also how do you find the length of the train?

Answer:

[tex]H = 273.4 m[/tex]

Explanation:

Let the falling object took "n" seconds to reach the ground and it travels H height

So we will have

[tex]H = \frac{1}{2}gn^2[/tex]

now we know that it covers one fourth of total height in last second

So we can say that it will cover 3H/4 distance in (n-1) seconds

so we will have

[tex]\frac{3H}{4} = \frac{1}{2}g(n-1)^2[/tex]

now from above two equations

[tex]\frac{4}{3} = (\frac{n}{n-1})^2[/tex]

[tex]1.155(n-1) = n[/tex]

[tex]n = 7.46 s[/tex]

Now we have

[tex]H = \frac{1}{2}(9.81)(7.46^2)[/tex]

[tex]H = 273.4 m[/tex]

Answer:

false

Explanation:

Final answer:

The resistive force of the apple on the arrow is 46.875 N in the direction opposite to the arrow’s travel, calculated using the work-energy theorem and the change in kinetic energy of the arrow as it passes through the apple.

Explanation:

To find this force, we can use the work-energy theorem which states that the work done on an object is equal to its change in kinetic energy. Since the arrow slowed down, the apple did work against the arrow's motion.

The change in kinetic energy (ΔKE) of the arrow can be calculated using the kinetic energy formula KE = 1/2 mv², where m is the mass of the arrow and v is its velocity. By finding the difference in kinetic energy at the entry and exit points of the arrow through the apple, we can determine the work done by the apple, which is equal to the force times the distance the force acted (in this case, the thickness of the apple).

ΔKE = 1/2 m(vf² - vi²) where vi = initial velocity and vf = final velocity.
ΔKE = 1/2 × 0.030 kg × (25.0² - 30.0²) m²/s²
ΔKE = -3.75 Joules (since the kinetic energy decreased).

The work done by the apple, W = ΔKE = -3.75 J (the negative sign indicates the force acted opposite the arrow's direction).
Using work (W) = force (F) × distance (d), we get:
F = W/d
F = (-3.75 J) / (0.080 m)
F = -46.875 N

So, the resistive force of the apple on the arrow is 46.875 N in the opposite direction of the arrow’s travel.

The force exerted by the apple resisting the arrow is 30.0 N.

The force exerted by the apple resisting the arrow can be calculated using Newton's second law of motion, which states that force (F) is equal to the change in momentum (Δp) divided by the time interval (Δt) over which the change occurs. Since the arrow's mass (m) is given as 30.0 grams and its initial and final velocities (v_i and v_f) are 30.0 m/s and 25.0 m/s, respectively, the change in momentum is calculated as Δp = m * (v_f - v_i). First, convert the mass to kilograms (1 g = 0.001 kg) to get 0.030 kg. Then, substitute the values into the formula:

Δp = 0.030 kg * (25.0 m/s - 30.0 m/s) = 0.030 kg * (-5.0 m/s) = -0.150 kg m/s.

The negative sign indicates that the momentum of the arrow decreases. As the arrow changes momentum, Newton's third law of motion tells us that the apple exerts an equal and opposite force on the arrow. Therefore, the force exerted by the apple on the arrow is 0.150 kg m/s divided by the time interval over which the change occurs. The time interval isn't provided, but for the purpose of this calculation, let's assume it's instantaneous (Δt = 0).

F = Δp / Δt = -0.150 kg m/s / 0 = -0.150 kg m/s² = -0.150 N.

However, this negative force indicates the force exerted by the arrow on the apple. To find the force exerted by the apple resisting the arrow, we take the magnitude of this force, which is 0.150 N. Thus, the force exerted by the apple resisting the arrow is 0.150 N, or 30.0 N in magnitude when considering the absolute value.

Answer:

The force that car A exerts on car B and the force that car B exerts on car A are the same magnitude.

Explanation:

There can be two types of collision i.e. elastic and inelastic collision. Elastic collision is also known as head-on collision. In this type of collision, the momentum and kinetic energy before and after the collision remains the same.

If two identical small cars (car A & car B) have a head-on collision, then the force that car A exerts on car B and the force that car B exerts on car A are the same magnitude. It is due to Newton's third law of motion which states that there is an equal and opposite reaction when one object applies a force on another object. So, the correct option is (c).  

A).

The tension in the rope when box is at rest is [tex]\fbox{\begin\\0\text{ N}\end{minispace}}[/tex].

Further Explanation:

The box, is tied to a horizontal rope, is placed on the surface of frictionless ice. The box is at rest and therefore, the velocity and acceleration of the box are zero.

Given:

The mass of the box, placed on the surface of frictionless ice, is [tex]50\text{ kg}[/tex].

The velocity of the box is [tex]0\text{ m/s}[/tex].

Concept:

The net force on the box, tied to the rope and placed on the surface of the frictionless ice, is equal to the product of mass of the box and the acceleration of the box.

The net force on the box is:

[tex]F=ma[/tex]                       ...... (1)

Here, [tex]m[/tex] is the mass of the box, [tex]a[/tex] is the acceleration of the box and [tex]F[/tex] is the net force on the box.

The box is placed on the surface of ice which is frictionless. Therefore, the net force on the box is equal to the tension produced in the rope.

The tension produced in the rope:

[tex]\fbox{\begin\\T=ma\end{minispace}}[/tex]                         ...... (2)

Here, [tex]T[/tex] is the tension produced in the rope.

Calculation:

Substitute the values in the equation (2).

[tex]\begin{aligned}\\T&=50\text{kg}\times0\\&=0\text{ N}\end{aligned}[/tex]

Thus, the tension in the rope when box is at rest is [tex]\fbox{\begin\\0\text{ N}\end{minispace}}[/tex].

B).

The tension in the rope when box is moving at a steady speed of [tex]5\text{ m/s}[/tex] is [tex]\fbox{\begin\\0\text{ N}\end{minispace}}[/tex].

Further Explanation:

The box is moving at the steady speed of [tex]5\text{ m/s}[/tex]. The acceleration of the box is zero because the rate of change of velocity with respect to time is zero.

Given:

The velocity of the box is [tex]5\text{ m/s}[/tex].

Calculation:

Substitute the values in the equation (2).

[tex]\begin{aligned}\\T&=50\text{kg}\times0\\&=0\text{ N}\end{aligned}[/tex]

Thus, the tension in the rope when box is moving at a steady speed of [tex]5\text{ m/s}[/tex] is [tex]\fbox{\begin\\0\text{ N}\end{minispace}}[/tex].

C).

The tension produced in the rope when the box is moving with velocity [tex]5\text{ m/s}[/tex] and it has acceleration [tex]5\text{ m}/\text{s}^2[/tex] is [tex]\fbox{\begin\\250\text{ N}\end{minispace}}[/tex].

Given:

The acceleration of the box is [tex]5\text{ m}/\text{s}^2[/tex].

The velocity of the box is [tex]5\text{ m/s}[/tex].

Calculation:

Substitute the values in the equation (2).

[tex]\begin{aligned}T&=50\text{ kg}\times5\text{ m}/\text{s}^2\\&=250\text{ N}\end{aligned}[/tex]

Thus, the tension produced in the rope when the box is moving with velocity [tex]5\text{ m/s}[/tex] and it has acceleration [tex]5\text{ m}/\text{s}^2[/tex] is [tex]\fbox{\begin\\250\text{ N}\end{minispace}}[/tex].

Learn more:

1.  Conservation of energy brainly.com/question/3943029

2.  The motion of a body under friction brainly.com/question/4033012

3. A ball falling under the acceleration due to gravity brainly.com/question/10934170

Answer Details:

Grade: High School

Subject: Physics

Chapter: Kinematics

Keywords:

Acceleration, frictionless surface, steady speed, tension in the rope, tension in the string, net force, ice-box system, 250N, 250 newton, 250 Newton, 0 N, 0 newton, 0 Newton, rope mass system, string mass system.

False

The Laissez-faire is a french term which means 'let you do' or leave alone. With regards to economics it refers to the least control of government in trade and business of the country. With regards to the polity, it refers to the least interference of government in the life of individual. So Laissez-faire situations are actually characterized by a least government involvement.

Answer:

A. Mutations can't result in a change in appearance.

Explanation:

A mutation is a sudden change in DNA that occurs at random in genetic material and can be transmitted to offspring. A mutation can also be caused by exposure to ultraviolet or ionizing radiation, chemical mutagens, or viruses. When the mutation occurs, it is permissible and continues with the individual until the day of death, as it is irreversible as it has modified the coding of DNA. When a mutation occurs, it can cause differences in the appearance of the individual, such as Down's syndrome, which changes not only the appearance, but the organism altogether. Therefore, we can consider that the answer to your question is the letter A.

To solve for F in the conversion formula, multiply both sides by 9/5 followed by adding 32 to isolate F. When converting 20 degrees Celsius using the formula, the result is 68 degrees Fahrenheit.

Part 1: Solving the equation for F

To solve the equation C = 5/9 (F - 32) for F, perform the following steps:

Multiply both sides by 9/5 to get rid of the fraction on the right side: 9/5 × C = F - 32.

Add 32 to both sides of the equation to isolate F on one side: 9/5 × C + 32 = F.

Part 2: Converting 20 degrees Celsius to Fahrenheit

To find out how many degrees Fahrenheit 20 degrees Celsius is, plug 20 into the rearranged equation:

F = (9/5) × 20 + 32.

Therefore, F = 36 + 32 = 68 degrees Fahrenheit.

Using the equations of motion, the length of the runway required for the 727 jet to take off can be determined. By calculating the acceleration and using the distance formula, we find that the runway must be at least 44.7039 meters long.

To determine the length of the runway required for the 727 jet to take off, we can use the equations of motion.

Therefore, the runway must be at least 44.7039 meters long for the 727 jet to take off.

The two balls meet at approximately 272.5 meters above the surface of the tower after around 5.1 seconds.

To determine when and at what height the two balls meet, we'll analyze their motions individually and then together.

Step 1: Motion of the dropped ball

For the ball dropped from the roof at a height of 400 meters, the equation of motion under gravity is:

h₁ = 400 - 0.5 * g * t²

where:

h₁ is the distance traveled by the dropped ball in meters.

g is the acceleration due to gravity (9.8 m/s²).

t is the time in seconds.

Putting in the values, h₁ = 400 - 4.9 t²

Step 2: Motion of the thrown ball

For the ball thrown upwards with an initial velocity of 50 m/s, the equation of motion is:

h₂ = 50t - 0.5 * g * t²

where:

h is the distance traveled by the thrown ball in meters.

Putting in the values, h₂ = 50t - 4.9 t²

Step 3: Equating the distances

The balls meet when their total distance is 400 meters, so:

h₁ + h₂ = 400

Substituting the equations for h₁ and h₂, 400 - 4.9 t² + 50t - 4.9 t² = 400

Simplifying, -9.8 t² + 50t = 0

Factoring out t, t(50 - 9.8t) = 0

Thus, t = 0 (initial point, not useful) or t = 50 / 9.8 ≈ 5.1 seconds.

Step 4: Calculating the height

Using t ≈ 5.1 seconds in any height equation:

h₁ = 400 - 4.9 * (5.1)²

h₁ = 400 - 127.5

h₁ ≈ 272.5 meters

Therefore, the two balls meet approximately 272.5 meters above the surface of the tower after about 5.1 seconds.

Answer: The correct option is Option b.

Explanation:

Power is defined as the rate of work done by an object.

Mathematically,

[tex]P=\frac{W}{t}[/tex]    .....(1)

And work done is the product of force exerted on the object times the displacement covered by that object.

Mathematically,

[tex]W=F.s[/tex]

Putting this value in above equation, we get:

[tex]P=\frac{F.s}{t}[/tex]

where,

P = power = ?W

F = Force exerted = 10N

s = Displacement = 400cm = 4m   (Conversion factor: 1m = 100 cm)

t = Time taken = 8s

Putting values in above equation, we get

[tex]P=\frac{10\times 4}{8}\\\\P=5W[/tex]

Hence, the correct option is Option b.

It's 200 on Edmentum

The scientist should use the constant l (triangle)H Vapor, the Latent heat of vaporization.

The latent heat of vaporization is the amount of heat required to change a unit mass of a liquid to vapor at its boiling point and vice versa.

Since the scientist wants to determine an efficient method for condensing large amounts of steam into liquid water, he should use (triangle)H Vapor.

Learn more about latent heat of vaporization at: https://brainly.com/question/9849439

#SPJ2

Speed and direction are the factors that affect an object's velocity.

The displacement that an object or particle experiences with respect to time is expressed vectorially as velocity. A vector quantity, that is. The change in an object's displacement with respect to time is known as velocity.

Displacement / Time = Velocity

The information is ,

Let V be the symbol for an object's velocity.

The measurement of V is now determined as

The concept of speed describes how quickly an object is traveling across a specific distance.

An object's speed just indicates how swiftly or slowly it is moving. It doesn't say which way the object is moving. Speed and direction are both referred to by the word velocity. A vector is an amount of velocity.

Now that the displacement is a vector quantity with direction, the equation for velocity is displacement / time.

As a result, an object's velocity is determined using its speed and direction.

Click here to learn more about velocity.

https://brainly.com/question/19979064

#SPJ6

Answer:

The correct answer is option C. "domains".

Explanation:

The regions within a magnet at which the magnetization is in a uniform direction are known as magnetic domains. These domains are group of atoms with aligned magnetic poles, this means that the magnetic moments of the atoms are aligned and that their point to the same direction. The magnetic domains are the ones that give the magnetic behavior of ferromagnetic materials.

1. Visible and shortwave radiation heat earth.

2. Earth radiates longwave radiation.

3. Longwave radiation is reflected downward.

4. Long wave radiation heats earth.

To find the stopping potential and the maximum speed of ejected electrons from a metal with a given work function when exposed to a specific wavelength of light, physicists use the photoelectric effect principles. Calculations involve the use of Planck's constant, the speed of light, and the electron charge to first determine the energy of incident photons and then the electrons' kinetic energy and velocity.

To determine the stopping potential for electrons ejected from a metal when light of wavelength 400 nm shines on it, first, we use the photoelectric equation: E(Photon) = Work Function + Kinetic Energy(Max). The energy of a single photon (E) can be found with the equation E=hc/λ, where h is Planck's constant (6.626 x 10^-34 J·s), c is the speed of light (3.00 x 10^8 m/s), and λ is the wavelength in meters. For the stopping potential, the maximum kinetic energy of the ejected electrons is equal to the electrical energy qV, where q is the charge of an electron (1.602 x 10^-19 C) and V is the stopping potential.

Using these equations and the given work function, the maximum speed of electrons can be calculated using the formula for kinetic energy: KE = 0.5 * m * v^2, where m is the mass of the electron (9.109 x 10^-31 kg) and v is the velocity.

The exact calculations for the stopping potential and maximum speed are not provided here, since we are not certain about the correctness of these specific answers.