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3 years ago

Which is an example of a physical change

Physics

1 answer:

mote1985 [20]3 years ago

6 0

Water boiling is an example of a physical change. The rest are chemical changes.
Hope that helps!!

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Use newton's law to explain the vertical acceleration of a projectile

NISA [10]

Answer:

Explained below

Explanation:

Newton's first law of motion: This law states that an object will remain at rest or continue in constant motion except it's acted upon by an external force. In projectile motion, the horizontal component of velocity will remain unchanged because we ignore air resistance since no force is acting in that horizontal direction.

Newton's second law of motion: This law states that force is the product of mass and acceleration. In projectile the force acts downwards, thus f = mg.

But g = a since internal forces will cancel out.

Thus, F = ma

5 0

3 years ago

Water flows without friction vertically downward through a pipe and enters a section where the cross sectional area is larger. T

djverab [1.8K]

Answer:

$v_{2}$ will be less than $v_{1}$ and $P_{2}$ will be greater than $P_{1}$ .

Explanation:

As we know from the conservation of mass, the rate at which any amount of fluid mass ( $m_{1}$ ) is entering in a system is equal to the rate at which the same amount of fluid mass ( $m_{2}$ ) is leaving the system.

Rate of mass flow can be written as,

$m = \rho A v$

where $\rho$ is the density of the fluid, $A$ is the area through which the fluid is flowing and $v$ is the velocity of the fluid.

Now, according to the problem, as the density of the fluid does not change, we can write

$&& m_{1} = m_{2}\\&or,& \rho A_{1} v_{1} = \rho A_{2} v_{2}\\&or,& \dfrac{v_{2}}{v_{1}} = \dfrac{A_{1}}{A_{2}}$

where $A_{1}$ and $A_{2}$ are the cross-sectional areas through which the fluid is passing and $v_{1}$ and $v_{2}$ are the velocities of the fluid through the respective cross-sectional areas.

As according to the problem, $A_{2} > A_{1}$ , so from the above formula $v_{2} < v_{1}$ .

Also we know that fluid pressure is created by the motion of the fluid through any area. When the fluid gains speed, some of its energy is used to move faster in the fluid’s direction of motion. It causes in a lower pressure.

So, as in this case $v_{2} < v_{1}$ the pressure in the large cross-sectional area $P_{2}$ will be greater than the pressure $P_{1}$ in the small cross sectional area, i.e.,

$P_{2} > P_{1}$ .

6 0

3 years ago

Help me pls, class starts soon

ratelena [41]

Answer:

Explanation:

1.)66.36

2.)11.4

3.)0.8104

4.)4158.315

i got some of them and try the rest good luck

4 0

2 years ago

The legislative branch has the power to (3 points)

maw [93]

Hi there!

The Legislative Branch of government includes the House of Representatives and the Senate. This branch makes laws. Its powers include passing laws, originating spending bills (House), impeaching government officials (Senate), and approving treaties (Senate).

Hope this helps!! :)
If there's anything else that I can help you with, please let me know!

3 0

3 years ago

Read 2 more answers

How can isotopes of a given element be identified?

marin [14]

Answer: All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. ... Each atomic number identifies a specific element, but not the isotope; an atom of a given element may have a wide range in its number of neutrons.

Explanation: Hopefully this helps. Have a great day.

6 0

3 years ago