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3 years ago

Questions

Physics

1 answer:

astra-53 [7]3 years ago

8 0

Answer:

1968

Explanation:

2400*20.5*0.004

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A positively-charged object with a mass of 0.129 kg oscillates at the end of a spring, generating ELF (extremely low frequency)

9966 [12]

Answer:308 N/m

Explanation:

Given

mass $\left ( m\right )=0.129 kg$

wavelength $\left ( \lambda \right )=3.86\times 10^7$

We know frequency = $\frac{c}{\lambda }=\frac{3\times 10^8}{3.86\tmes 10^7}$

f=7.772 Hz

As the frequency of radio waves is same as the frequency at which object oscillates

$f=\frac{1}{2\pi }\sqrt{\frac{k}{m}}$

$7.772=\frac{1}{2\pi }\sqrt{\frac{k}{0.129}}$

$7.772\times 2\times \pi =\sqrt{\frac{k}{0.129}}$

$k=307.70\approx 308 N/m$

7 0

4 years ago

1)<br> How much time does it take to lift a box using 18.0 J of work and 20.89 Watt of power?

oee [108]

Answer:.

Explanation:

7 0

3 years ago

A 0.25-m string, vibrating in its sixth harmonic, excites a 0.96-m pipe that is open at both ends into its second overtone reson

Andrews [41]

Answer:

option D

Explanation:

given,

length of the pipe, L = 0.96 m

Speed of sound,v = 345 m/s

Resonating frequency when both the end is open

$f = \dfrac{nv}{2L}$

n is the Harmonic number

2nd overtone = 3rd harmonic

so, here n = 3

now,

$f = \dfrac{3\times 345}{2\times 0.96}$

f = 540 Hz

The common resonant frequency of the string and the pipe is closest to 540 Hz.

the correct answer is option D

7 0

3 years ago

Can an object contain heat? Why or why not?

Stells [14]

Every object has thermal energy (better word than heat, since we associate that with high temperatures). This is actually the molecules vibrating, moving a lot. More thermal energy means more vibrating, and thus also expanding in volume.

8 0

3 years ago

4.) An apartment building is on fire and a guy is trapped on the fire escape ladder. There is a

Tems11 [23]

Answer:

5.3 m/s

Explanation:

First, find the time it takes for him to fall 7m.

y = y₀ + v₀ t + ½ at²

0 = 7 + (0) t + ½ (-9.8) t²

0 = 7 − 4.9 t²

t ≈ 1.20 s

Now find the velocity he needs to travel 6.3m in that time.

x = x₀ + v₀ t + ½ at²

6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²

v₀ ≈ 5.27 m/s

Rounded to two significant figures, the man must run with a speed of 5.3 m/s.

3 0

3 years ago