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3 years ago

We can block light by placing obstacles in its path, but it’s much more difficult to block sound. Why?

2 answers:

8 0

It's harder to block sound because sound waves and transverse waves, causing the sound to bounce off objects. This isn't the same with light. Hope that helps.

rjkz [21]3 years ago

5 0

All we have to do is focus on what you want to hear and you can tell your mind to block everything out and its very easy to block light than noise all you have to do is focus

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65. A length of wire is bent into a closed loop and a magnet is plunged into it, inducing a voltage and, consequently, a current

natulia [17]

Answer:

Resistance of the second wire is twice the first wire.

Explanation:

Let us first see the formula of resistance;

R = pxL/A

Here L is the lenght of the wire, A the area and p is the resistivity of wire.

As we are given that the length of second wire is double than that of the first wire, hence the resistance of second wire would be double.

Since we have two loop in second case, inducing double voltage but as resistance is doubled so the current would remain same according to ohms law

I = V/R

6 0

3 years ago

Read 2 more answers

What is meant by global warming?

pychu [463]

The global warming is the uniform heating of the globe due to the effect of greenhouse gases.

Answer: Option B

<u>Explanation:</u>

Global warming is thus the theory that says that earth is warming up with an increase in temperature over time due to increment in the greenhouse gases.

These are greenhouse gases that are getting increased due to the human activity or say over exploitation of the natural resources. The heating of the globe has caused ozone layer depletion which is also causing warming.

6 0

3 years ago

Se dispone de dos vasos con agua a 20 grados y queremos calentarlo hasta alcanzar 50 grados. Si el primero contiene 0,5l y el se

BigorU [14]

Answer:

The cup with 0.5L

Explanation:

To know what amount of water you take into account the specific heat of the water. The specific heat of water is:

$c_{water}=4186\frac{J}{kg\°C}$

Thus, 4186 J of energy are needed to icrease the temperature of 1 kg water in 1°C. Then, more grams of water will need more energy.

You have that one cup has 0.5 L and the other one has 750mL = 0.75L

The second cup of water will need more heat because the amount of water contained in the second cup is greater than in the first cup with 0.5L

4 0

3 years ago

A body travels 30m in 5s, 45m in 7s and then 65m in the last 5s. Find the average speed of the body

JulijaS [17]

We can find the average speed of the body by finding the total distance covered, and then dividing it by the total time of the motion.

The total distance covered is:
$S=30 m + 45m+65m=140 m$

while the total time of the motion is
$t=5 s+7s+5 s=17 s$

So, the average speed of the body is:
$v= \frac{S}{t}= \frac{140 m}{17 s}=8.24 m/s$

8 0

3 years ago

A 2.00 kg ball is thrown upward at Some unknown angle from the top of a 20.0 M high building If the initial magnitude of the vel

mixer [17]

Answer:

792 J

Explanation:

The total energy of the ball is E = U + K where U = potential energy = mgh and K = kinetic energy = 1/2mv²

E = mgh + 1/2mv² where m = mass of ball = 2.0 kg, g = acceleration due to gravity = 9.8 m/s², h = height of building = 20.0 m, v = initial velocity of ball = 20.0 m/s.

So, substituting the values of the variables into E, we have

E = mgh + 1/2mv²

= 2.00 kg × 9.8 m/s² × 20.0 m + 1/2 × 2.00 kg × (20.0 m/s)²

= 392 J + 400 J

= 792 J

6 0

3 years ago