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3 years ago

For the examples below, explain what a physical change or a chemical change has occurred. Justify your answer

1 answer:

4 0

A. chemical change, a new substance is formed and the effect cannot be undone.
B.physical change, there is no new substance made and the effect can be undone
C.chemical change, the effect cannot be undone
D.physical change, the effect can be undone
E.chemical change, a new substance is made and the effect cannot be undone
F.physical change, there is no new substance and the effect can be reversed

hope this helps :)

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What controls whether a lava flow is aa or pahoehoe

nevsk [136]

Explanation:

Basaltic lava

Basaltic lava generally takes two distinct forms known by the Hawaiian terms pahoehoe and aa. Pahoehoe has a smooth wavy surface that resembles twisted rope. It advances by extruding molten toes of lava beneath a thin, flexible crust. As it travels pahoehoe lava often changes to blocky flows called aa.

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3 years ago

When using science to investigate physical phenomena, which characteristic of the event must exist?

murzikaleks [220]

In my opinion, the correct answer from the choices listed above would be the second option. When using science to investigate physical phenomena, the event should be observable. Hope this answers the question. Have a nice day. Feel free to ask more questions.

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3 years ago

Read 2 more answers

An 85.0-N crate of apples sits at rest on a ramp that runs from the ground to the bed of a truck. The ramp is inclined at 28.0°

irina [24]

Answer:

A 75.1 N and a direction of 152° to the vertical.

B 85.0 N at 0° to the vertical.

Explanation:

A) The interaction partner of this normal force has what magnitude and direction?

The interaction partner of this normal force is the component of the weight of the crate perpendicular to the ramp. It has a magnitude of 85cos28° = 75.1 N and a direction of 180° - 28° = 152° to the vertical(since it is directed downwards perpendicular to the ramp).

B) The normal and frictional forces are perpendicular components of the contact force exerted on the crate by the ramp. What is the magnitude and direction of the contact force?

Since this force has to balance the weight of the crate, its magnitude is 85.0 N. Its direction has to be vertically opposite to that of the weight.

Since the weight is 180° to the vertical (since it is directed downwards), this force is 0° to the vertical.

So, this force has a magnitude of 85.0 N and a direction of 0° to the vertical.

8 0

3 years ago

Serving at a speed of 164 km/h, a tennis player hits the ball at a height of 2.23 m and an angle θ below the horizontal. The ser

sweet-ann [11.9K]

Answer:

The angle θ is 6.1° below the horizontal.

Explanation:

Please, see the figure for a description of the situation.

The vector "r" gives the position of the ball and can be expressed as the sum of the vectors rx + ry (see figure).

We know the magnitude of these vectors:

magnitude rx = 11.6 m

magnitude ry = 2.23 m - 0.99 m = 1.24 m

Then:

rx = (11. 6 m, 0)

ry = (0, -1.24 m)

r = (11.6 m + 0 m, 0 m - 1.24 m) = (11.6 m, -1.24 m)

Using trigonometry of right triangles:

magnitude rx = r * cos θ = 11. 6 m

magnitude ry = r * sin θ = 2.23 m - 0.99 = 1.24 m

where r is the magnitude of the vector r

magnitude of vector r:

$r = \sqrt{(11.6m)^{2} + (1.24m)^{2}} = 11.667m$

Then:

cos θ = 11.6 m / 11.667 m

θ = 6.1°

Using ry, we should obtain the same value of θ:

sin θ = 1.24 m/ 11.667 m

θ = 6.1°

( the exact value is obtained if we do not round the module of r)

7 0

3 years ago

What is the highest-frequency sound to which this machine can be adjusted without exceeding the prescribed limit

Tresset [83]

The highest frequency sound to which the machine can be adjusted is :

4179.33 Hz

Given data :

Pressure = 10 Pa

Speed of sound = 344 m/s

Displacement altitude = 10⁻⁶ m

<h3>Determine the highest frequency sound ( f ) </h3>

applying the formula below

Pmax = $B(\frac{2\pi f}{v}) A$ --- ( 1 )

Therefore :

f = ( Pmax * V ) / $2\pi \beta A$

= ( 10 * 344 ) / 2 $\pi$ * 1.31 * 10⁵ * 10⁻⁶

= 4179.33 Hz

Hence we can conclude that The highest frequency sound to which the machine can be adjusted is : 4179.33 Hz .

Learn more about Frequency : brainly.com/question/25650657

Attached below is the missing part of the question

A loud factory machine produces sound having a displacement amplitude in air of 1.00 μm, but the frequency of this sound can be adjusted. In order to prevent ear damage to the workers, the maximum pressure amplitude of the sound waves is limited to 10.0 Pa. Under the conditions of this factory, the bulk modulus of air is 1.31×105 Pa. The speed of sound in air is 344 m/s. What is the highest-frequency sound to which this machine can be adjusted without exceeding the prescribed limit?

4 0

2 years ago