Answer:
I think they use it at night because they want to avoid involving themselves in road accident while crossing the street. When there are reflective strips on their clothes, drivers do notice them even at far ends of the street since the strips will reflect the rays from the car lights to the driver,hence, the driver notifies that there is a pedestrian crossing and therefore slows down.
Answer:
346.66 Hz
Explanation:
= Length of string which is unfingered = l
= Length of string which is vibrate when fingered = 
= Unfingered frequency = 260 Hz
= Fingered frequency
Frequency is inversely proportional to length

So,

The frequency of the fingered string is 346.66 Hz
When you attract every object in the universe with a force that is proportional to the mass of the objects and to the distance between them, we are obeying Newton's law of universal gravitation.
<h3>Newton's law of universal gravitation</h3>
Newton's law of universal gravitation states that the force of attraction between two masses in the universe is directly proportional to the product of the masses and inversely proportional to the the square of the distance between them.
The mathematical interpretation of the above law is
Removing the proportionality sign,
Where:
- F = Force of attraction
- G = Gravitational constant
- M = Bigger mass
- m = Smaller mass
- r = Distance between the masses.
From the above, When you attract every object in the universe with a force that is proportional to the mass of the objects and to the distance between them, we are obeying Newton's law of universal gravitation.
Learn more about Newton's law of universal gravitation here: brainly.com/question/9373839
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To get a uniform field in the central region between the coils, current flows in the same direction in each.
Because their blood cells could be transfused to any blood type
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