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2 years ago

Which of the following is a physical change

Physics

1 answer:

topjm [15]2 years ago

6 0

Answer: A physical change can be a change in size, shape, or color.

Explanation:

One type of physical change is a phase change. Consider water for example, if liquid water evaporated into a vapor, a phase change occurred. A phase change is a type of physical change. The difference between a physical change and chemical change is that a physical change doesn't change the substance identity. A chemical change can however change the identity of the substance.

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The index of refraction is the ratio of the speed of light in a vacuum to the speed of light in a medium. Which true statement i

Alika [10]

Answer:

A. Materials with a low index of refraction cause light to refract very little.

7 0

2 years ago

Read 2 more answers

Find the order of magnitude of your age in seconds

Natali5045456 [20]

The order of magnitude of my age in seconds is 10^9. I think you'll find that this is true for anyone who is 32 or older.

6 0

2 years ago

A river flows with a speed of 0.600 m/s. A student first swims upriver 0.500 km, then turns around and returns to his starting p

DerKrebs [107]

Answer:

a) 1111.0 seconds

b) 833.3 s

c) Because of proportions

Explanation:

a) Total time of round trip is the sum of time upriver and time downriver

$t_{total}=t_{up}+t_{down}$

Time upriver is calculated with the net speed of student and 0.500 km:

$t_{up}=\frac{d_{istance}}{|v_{swimmer}|} ;\\v_{swimmer}=v_{relative to river}+v_{river}=-1.2+0.6=-0.6 m/s\\t_{up}=\frac{500 m}{0.6 m/s}=833.3 s$

(Becareful with units 0.5 km= 500m) Similarly of downriver:

$t_{down}=\frac{d_{istance}}{|v_{swimmer}|} ;\\v_{swimmer}=1.2+0.6=1.8 m/s\\t_{down}=\frac{500 m}{1.8 m/s}=277.7 s$

So the sum is:

$t_{total}=1111.0s$

b) Still water does not affect student speed, so total time would be simply:

$t_{total}=\frac{1000 m}{1.2 m/s}=833.3 s$

c) For the upriver trip, student moved half the distance in half speed of the calculation in b), so it kept the same ratio and therefore, same time. So the aditional time is actually the downriver.

6 0

2 years ago

Two long, straight wires are parallel and 26 cm apart.

mezya [45]

Answer: 2.49×10^-3 N/m

Explanation: The force per unit length that two wires exerts on each other is defined by the formula below

F/L = (u×i1×i2) / (2πr)

Where F/L = force per meter

u = permeability of free space = 1.256×10^-6 mkg/s^2A^2

i1 = current on first wire = 57A

i2 = current on second wire = 57 A

r = distance between both wires = 26cm = 0.26m

By substituting the parameters, we have that

Force per meter = (1.256×10^-6×57×57)/ 2×3.142 ×0.26

= 4080.744×10^-6/ 1.634

= 4.080×10^-3 / 1.634

= 2.49×10^-3 N/m

5 0

2 years ago

Please help me and thank you

fredd [130]

Answer:

536.56 m/s

Explanation:

We'll begin by calculating the momentum of the Porsche. This can be obtained as follow:

Mass (m) of Porsche = 1361 kg

Velocity (v) of Porsche = 26.82 m/s

Momentum of Porsche =?

Momentum = mass × velocity

Momentum = 1361 × 26.82

Momentum of Porsche = 36502.02 Kgm/s

Finally, we shall determine the velocity you need to be running with in order to have the same momentum as the Porsche. This can be obtained as follow:

Your Mass = 68.03 kg

Your Momentum = Momentum of Porsche = 36502.02 Kgm/s

Your velocity =?

Momentum = mass × velocity

36502.02 = 68.03 × velocity

Divide both side by 68.03

Velocity = 36502.02 / 68.03

Velocity = 536.56 m/s

Thus you must be running with a speed of 536.56 m/s in order to have the same momentum as Porsche.

8 0

2 years ago