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Digiron [165]
2 years ago
11

Directions: Consider a 2-kg

Physics
1 answer:
nignag [31]2 years ago
7 0

The definition of mechanical energy allows to find the results for the questions about the energy changes in the movement of the system are:

     1) The midpoint of the path. Em = 784 J

     2) Lowest point of the trajectory Em = 784 J

     3) Acceleration of gravity is: g = 9.8 m/s²

     4) The bowling ball has more kinetic energy as its height decreases.

<h3>Mechanical energy.</h3>

Mechanical energy is the sum of the kinetic energy due to motion and the potential energies of the body. In the case of no friction the energy remains constant at all points, this is one of the most important principles of physics.

          Em = K + U

          Em = ½ m v² + m g h

Where Em is the mechanical energy, K and U the kinetic and potential energy, respectively, m the mass, v the velocity. G the acerleacion of gravity and h the height where the body is.

In this case when the ball is on top of the building of height y = 40 m, all its energy is potential.

           Em = U = m g h

           Em = 2 9.8 40

            Em = 784 J

when the body falls it begins to acquire speed, therefore its kinetic energy increases and the height decreases, therefore its potential energy decreases, but the sum of the two remains constant.

1) Let's calculate the energy at the midpoint of the path.

They indicate that the speed is v= 19.8 m/s and the height is y2 = 20m

         Em = ½ m v² + m g h

         em = ½ 2 19.8 ² + 2 9.8 20

         em = 392 + 392

         Em = 784 J

We see that the kinetic and potential energy have the same value and the mechanical energy maintains its initial value.

2) We calculate the energy at the lowest point of the trajectory.

They indicate that the speed is v= 28 m/s and = height is zero h=0

Let's calculate

          Em = ½ m v² + m g h

          Em = ½ 2 28² + 0

          Em = 784 J

At this point, all energy is kinetic and mechanical energy is conserved.

3) The acceleration of gravity comes from Newton's second law where the force is the universal attraction.

           F = G \frac{Mm}{r^2}

           F= ma

           \G frac{Mm}{R^2}

In the case of a body near thesurfacee of the distance of the radius of the planet and the acceleration is called gravity

            g = a = G \frac{M}{R_e^2 }

            g = \frac{ 6.67 \ 10^{-11} \ 5.98 \ 10^{24}}{6.37 \ 10^6 }

            g = 9.81  m/s²

4) The bowling ball has more kinetic energy as its height decreases, at the point where the height is half the kinetic and potential energy are equal.

In conclusion using the definition of mechanical energy we can find the results for the questions about the energy changes in the movement of the system are:

     1) The midpoint of the path. Em = 784 J

     2) Lowest point of the trajectory Em = 784 J

     3) Acceleration of gravity is: g = 9.8 m/s²

     4) The bowling ball has more kinetic energy as its height decreases.

Learn more about mechanical energy here:  brainly.com/question/24443465

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If a seismic wave has a period of 0.0202s, find the frequency of the wave.
maw [93]

Answer:

49.5 Hz.

Explanation:

From the question given above, the following data were obtained:

Period (T) = 0.0202 s

Frequency (f) =?

The frequency and period of a wave are related according to the following equation:

Frequency (f) = 1 / period (T)

f = 1/T

With the above formula, we can obtain the frequency of the wave as follow:

Period (T) = 0.0202 s

Frequency (f) =?

f = 1/T

f = 1/0.0202

f = 49.5 Hz

Therefore the frequency of the wave is 49.5 Hz.

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3 years ago
Example sentence for gravitational potential energy
andreev551 [17]

Answer:

Explanation:

An object falling loses gravitational potential energy and gains kinetic energy. The gravity potential is the gravitational potential energy per unit mass. This energy comes from the gravitational potential energy released when the water falls. ... At 0, all the energy is in gravitational potential energy.

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A box is at rest on a table. What can you say about the forces acting on the box?
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8 0
3 years ago
Read 2 more answers
The top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it.
Lesechka [4]

The top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it. Because the contact between the bolt and the   pliers working surface is less.

<h3>What is mechanical advantage ?</h3>

Mechanical advantage is a measure of the ratio of output force to input force in a system, it is used to obtained efficiency of the given mechanical machine.

The efficiency to open the stubborn bolt depends upon the contact between the working surface of the pliers and the bolt.

The contact between the bolt and the top pair of pliers working surface is less. Its mechanical advantage is less.

Hence, the top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it.

To learn more about the mechanical advantage, refer to the link;

brainly.com/question/7638820

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3 0
2 years ago
A car is traveling at 15 m/sm/s . Part A How fast would the car need to go to double its kinetic energy
GREYUIT [131]

Answer:

21.21 m/s

Explanation:

Let KE₁ represent the initial kinetic energy.

Let v₁ represent the initial velocity.

Let KE₂ represent the final kinetic energy.

Let v₂ represent the final velocity.

Next, the data obtained from the question:

Initial velocity (v₁) = 15 m/s

Initial kinetic Energy (KE₁) = E

Final final energy (KE₂) = double the initial kinetic energy = 2E

Final velocity (v₂) =?

Thus, the velocity (v₂) with which the car we travel in order to double it's kinetic energy can be obtained as follow:

KE = ½mv²

NOTE: Mass (m) = constant (since we are considering the same car)

KE₁/v₁² = KE₂/v₂²

E /15² = 2E/v₂²

E/225 = 2E/v₂²

Cross multiply

E × v₂² = 225 × 2E

E × v₂² = 450E

Divide both side by E

v₂² = 450E /E

v₂² = 450

Take the square root of both side.

v₂ = √450

v₂ = 21.21 m/s

Therefore, the car will travel at 21.21 m/s in order to double it's kinetic energy.

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2 years ago
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