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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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American space pilots were called astronauts. What were soviet space pilots called?.

Mnenie [13.5K]

Answer:

Cosmonauts

Explanation:

As the americans are called astronauts which means star sailors and the russians (soviet space pilots) are called cosmonauts which means sailors of the universe

4 0

3 years ago

If a girl is running along a straight road with a uniform velocity 1.5 m/s, find her

Dafna1 [17]

Answer:

Explanation:

The definition of acceleration is the change in velocity over a period of time. If the girl's velocity is constant, that means it's not changing. Therefore, acceleration is 0 m/s/s

7 0

3 years ago

A railroad car moving at a speed of 3.49 m/s overtakes, collides, and couples with two coupled railroad cars moving in the same

Mandarinka [93]

Answer:

Explanation:

Using conservation law of momentum

let m₁ = mass of the railroad, initial u₁ = 3.49 m/s

let m₂ = mass of one of the coupled car, u₂= 1.28m/s

let m₃ = mass of the second car u₃ = 1.28 m/s

m₁u₁ + m₂u₂ + m₃u₃ = v ( m₁ + m₂ + m₃)

since the masses are the same

m₁ = m₂ = m₃

m ( 3.49 + 1.28 + 1.28) = 3m v

6.05 m = 3 mv

v = 6.05 m / 3m = 2.0167 m/s

b) kinetic energy lost = energy before collision - energy after collision

= (0.5m₁u₁² + 0.5 ( m₁+m₂) u₂² - 0.5 ( m₁ + m₂ + m₃) v

= (6.58365 + 1.7712) - 6.5951 = 1.76J

7 0

3 years ago

3. A car travelling at 20. m/s stops in a distance of 40. m. What is its

KIM [24]

Answer:

It was a joke i was getting the answer

Explanation:

Be percent karen

4 0

3 years ago

The deck of a bridge is suspended 235 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of

Aleks04 [339]

Answer:

(a) 1, average velocity = -65.6 m/s

2, average velocity = -64.8 m/s

3, average velocity = -64.16 m/s

(b) The instantaneous velocity is -96 m/s

Explanation:

(a)

Average velocity is given by;

$y(t_2,t_1) = \frac{y(t_2) - y(t_1)}{t_2-t_1}$

(1)

$y(2.1,2) = \frac{(235-16*2.1^2) - (235-16*2^2)}{2.1-2}\\\\ y(2.1,2) = -65.6 \ m/s$

(2)

$y(2.05,2) = \frac{(235-16*2.05^2) - (235-16*2^2)}{2.05-2}\\\\ y(2.05,2) = -64.8 \ m/s$

(3)

$y(2.01,2) = \frac{(235-16*2.01^2) - (235-16*2^2)}{2.01-2}\\\\ y(2.01,2) = -64.16 \ m/s$

b. y = 235 - 16t²

The instantaneous velocity is given by;

v = dy /dt

dy / dt = -32t

when t = 3 s

v = -32(3)

v = -96 m/s

5 0

3 years ago