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3 years ago

Why does the total amount of energy before and after any energy transformations remain the same?

2 answers:

8 0

The Law of Conservation of Energy states that, in an isolated system, energy remains constant and can not be created or destroyed, only transferred from one form to another. This law was created by Julius Robert Mayer.

STALIN [3.7K]3 years ago

3 0

Answer:

This is because energy can neither be created or destroyed but can only be transferred from one state to the other

Explanation:

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In a first order decomposition in which the rate constant is 0.204 sec-1, how long will it take (in seconds) until 0.399 mol/L o

DENIUS [597]

Answer:

2.902 to 3 decimal places

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3 years ago

In world war 1 , Multiple reflection was used in submarines. How multiple reflection works and helps in such situation?

prisoha [69]

Answer:

Submarines use a device called Periscope that uses the concept of multiple reflections and help us see objects above the water surface.

Explanation:

When a light ray falls on a reflecting surface like a mirror, it gets reflected. In multiple reflections, the incident light ray is made to reflect multiple times by arranging the reflecting surfaces in different ways.

In submarines, we use Periscope, which is a long tube like structure. The long tube is bent at ends. It uses two simple mirrors which are placed parallel to each other at an angle of 45 degrees. The light from one mirror gets reflected to the other mirror, thus causing a multiple reflection.

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3 years ago

A silver wire has a cross sectional area a = 2.0 mm2. a total of 9.4 × 1018 electrons pass through the wire in 3.0 s. the conduc

marta [7]

This problem uses the relationships among current I, current density J, and drift speed vd. We are given the total of electrons that pass through the wire in t = 3s and the area A, so we use the following equation to to find vd, from J and the known electron density n, so:

$v_{d} = \frac{J}{n\left | q \right |}$

The current I is any motion of charge from one region to another, so this is given by:

 $I = \frac{\Delta Q}{\Delta t} = \frac{9.4x1018electrons}{3s} = 3189.73(A)$

The magnitude of the current density is:

$J = \frac{I}{A} = \frac{3189.73}{2x10^{-6}} = 1594.86(A/m^{2})$

Being:

$A=2mm^{2} = 2x10^{-6}m^{2}$

Finally, for the drift velocity magnitude vd, we find:

 $v_{d} = \frac{1594.86}{5.8x1028\left |1.60x10^{-19}|\right } = 1.67x10^{18}(m/s)$

Notice: The current I is very high for this wire. The given values of the variables are a little bit odd

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3 years ago

Transfer of heat through conduction can occur in which of the following?

lianna [129]

Answer:d I think

Explanation:

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2 years ago

Read 2 more answers

Pls pls pls pls help!!!!!

Natasha2012 [34]

Answer:

The net upward force the man experiences is approximately 1,324.8 N

The net downward force the man experienced is approximately 556.8 N

Explanation:

The given mass of the man, m = 96 kg

The acceleration of the elevator, a = 4.0 m/s²

According to Newton's third law of motion which states that action ad reaction are equal and opposite, when the elevator moves upwards, we have;

The net force the man experiences, F = Gravitational force, m·g + The force of the elevator pushing upwards, m·a

∴ ↑F = m·g + m·a

Where;

F = The net force the man experiences

m = The mass of the man = 96 kg

g = The acceleration due to gravity ≈ 9.8 m/s²

a = The acceleration of the elevator = 4 m/s²

∴ ↑F = 96 kg × 9.8 m/s² + 96 kg × 4 m/s² ≈ 1,324.8 N

The net upward force the man experiences ≈ 1,324.8 N

When the elevator moves downwards, we have;

The net force the man experiences, F = Gravitational force, m·g + The loss of the gravitational force as the floor moves further downwards, -(m·a)

∴ F = m·g + -(m·a) = m·g - m·a

F = m·g - m·a

∴ ↓F = 96 kg × 9.8 m/s² - 96 k × 4 m/s² ≈ 556.8 N

The net downward force the man experienced ≈ 556.8 N

8 0

2 years ago