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joja [24]
3 years ago
13

A boy yells in a narrow valley. The sound reflects off of a boulder that is 80 m away. How long will it take to hear the echo if

Physics
2 answers:
soldier1979 [14.2K]3 years ago
4 0

Answer:4 lubeconds (speed=distance over time)

Dima020 [189]3 years ago
3 0

Answer:

Time taken, t = 0.5 seconds

Explanation:

It is given that,

Speed of sound wave, v = 320 m/s

The sound reflects off of a boulder that is 80 m away.

Let t is the time taken to hear the echo. The distance covered by the sound to hear the echo is, 2d. So,

v=\dfrac{2d}{t}

t=\dfrac{2d}{v}  

t=\dfrac{2\times 80\ m}{320\ m/s}

t = 0.5 seconds

So, the time taken to hear the echo is 0.5 seconds. Hence, this is the required solution.

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In separate experiments, a large number of particles (all with the same charge but with a wide variety of masses, speeds, and sp
melomori [17]

The particles that move in orbits of the same radius have the same momentum.

<h3>Orbital angular momentum:</h3>

A point particle's three-dimensional angular momentum is traditionally represented by the pseudovector r p, which is the cross product of the particle's position vector r (relative to some origin) and momentum vector, which in Newtonian physics is denoted by p = mv.

L = mrV_{prep} = mr²w is the particle's orbital angular momentum in units of magnitude. The part of the particle's velocity that is here perpendicular to the axis of rotation is designated as V_{perp.} The right-hand rule indicates the direction of the angular momentum. In isolated systems, the angular momentum is conserved.

Learn more about momentum here:

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4 0
2 years ago
An ac series circuit contains a resistor of 20 ohms, a capacitor of 0.75 microfarads of 120 x 10-3 H. If an effective (rms) volt
pav-90 [236]

Answer:

The effective (rms) current when the circuit is in resonance is 6 A

Explanation:

Given;

resistance of the resistor, R = 20 ohms

capacitance of the capacitor, C = 0.75 microfarads

inductance of the inductor, L =  0.12 H

effective rms voltage, V_{rms} = 120

At resonance, the impedance Z = R, Since the capacitive reactance (Xc) is equal to inductive reactance (XL).

The effective (rms) current, = V_{rms} / R

                                              = 120 / 20

                                              = 6 A

Therefore, the effective (rms) current when the circuit is in resonance is 6 A

3 0
3 years ago
Once carbon begins burning in the core of a high-mass star, the outer layers begin to fall inward, driving up the fusion rates a
sammy [17]

Answer:

Fusion rates and star evolution increase rapidly because of the conversion of hydrogen molecules to helium.

Explanation:

At the early stage of a star mass, hydrogen atoms are produced. After a few billion years, these hydrogen atoms formed at the core of the star mass begin to fuse on the external side of the core. Hydrogen atoms get rapidly fused, resulting to a contraction of the star core, and as more hydrogen atoms get fused, helium atoms are formed.

This action results into rapid into a rapid and violent burning action of hydrogen atoms around the core.

6 0
3 years ago
300 grams of ethanol is heated with 14640 Joules of energy to reach a final temperature of 30 °C. What was the initial temperatu
levacccp [35]

Answer:

10 °C

Explanation:

Applying

q = cm(t₂-t₁)............... Equation 2

Where q = heat energy, c = specific heat of ethanol, m = mass of ethanol, t₁ = initial temperature, t₂ = Final temperature.

Given: c = 2.44 J/g.°C,  m = 300 g, q = 14640 J, t₂ = 30°C

Substitute into equation 2 and solve for t₁

14640 = 2.44×300(30-t₁)

14640 = 732(30-t₁)

732(30-t₁) = 14640

(30-t₁)  = 14640/732

(30-t₁)  = 20

t₁ = 30-20

t₁ = 10 °C

6 0
3 years ago
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Rank the following in terms of increasing momentum:
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It’s b because if you’re running at 5 miles per second being a 100kg weight is the fastest
5 0
4 years ago
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