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Svetlanka [38]
3 years ago
7

3. A train covers 168 km in 4 hours. How much distance will it cover in 80 minutes?

Physics
1 answer:
Kay [80]3 years ago
4 0

Answer:

56km

Explanation:

168 ÷ 240 = 0.7

0.7 × 80 = 56km

240 is the amount of minutes in 4 hours.

We divided 168 by 240 to get the distance covered in 1 minute. Afterwards, we needed 80 minutes so we multiplied the answer by 80.

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What happens to the frequency of a wave If the wavelength is decreased by half
podryga [215]

Answer:

Frequency  doubles.

Explanation:

Frequency doubles because Wavelength and Frequency are inversely proportional. That means if one decreases the other one increases. So, if wavelength is half, frequency is the opposite, doubles.

8 0
3 years ago
If a hockey puck is made to slide along a straight line on a completely frictionless surface, which statement about the motion o
77julia77 [94]
C. the hockey puck will accelerate and continue moving in a straight line
8 0
3 years ago
Read 2 more answers
An electron accelerates through a 12.5 V potential difference, starting from rest, and then collides with a hydrogen atom, excit
Yanka [14]

Answer:

Initial state    Final state

     3           ⇒        2

     3           ⇒        1

     2          ⇒         1

Explanation:

For this exercise we must use Bohr's atomic model

         E = - 13.606 / n²

where is the value of 13.606 eV is the energy of the ground state and n is the integer.

The energy acquired by the electron in units of electron volt (eV)

          E = e V

          E = 12.5 eV

all this energy is used to transfer an electron from the ground state to an excited state

        ΔE = 13.6060 (1 / n₀² - 1 / n²)

the ground state has n₀ = 1

       ΔE = 13.606 (1 -  1/n²)

        1 /n² = 1 - ΔE/13,606

         1 / n² = 1 - 12.5 / 13.606

         1 / n² = 0.08129

          n = √(1 / 0.08129)

          n = 3.5

 since n is an integer, maximun is

         n = 3

because it cannot give more energy than the electron has

From this level there can be transition to reach the base state.

 

Initial state    Final state

     3           ⇒        2

     3           ⇒        1

     2          ⇒         1

8 0
3 years ago
You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. (a) If
dem82 [27]

Answer:

A) If you want to achieve the SMALLEST possible resistance, you should attach the leads to the opposite faces that measure b) 5 cm by 8 cm.

B) If you want to achieve the LARGEST possible resistance, you should attach the leads to the opposite faces that measure a) 3 cm × 5 cm

Explanation:

Resistivity is directly proportional to lenght and inversely properly to cross sectional area.

For the first case, 5 cm by 8 cm gives the largest area and leave 3 cm as the lenght. The resistivity of the metal will be smallest in these dimensions.

For the second case, 3 cm by 5 cm gives the smallest area, leaving 8 cm as the lenght. This is the maximum arrangement that can give the largest resistance possible.

4 0
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How efficient are the small and large scale solar-power systems used in individual homes and industrial settings?
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Answer:

I study physics too, want me to study with you?

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