<span>So we want to know what statement is an accurate description of vibrations. So humans can hear sound frequencies from 20-20000 Hz. Below 20 Hz is infra sound and above 20000 Hz is ultra sound. Humans cant hear both infra sound and ultra sound so the correct answer is A.</span>

6 0

3 years ago

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A bullet leaves a gun with a horizontal velocity of 100 m/s. Calculate the distance it would travel in 1.3 seconds.

salantis [7]

Answer:

130m

Explanation:

You just have to multiply velocity by the time traveled:

100m/s * 1.3s = 130m!

5 0

3 years ago

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An experiment is done to compare the initial speed of projectiles fired from high-performance catapults. The catapults are place

anzhelika [568]

Answer:1.084

Explanation:

Given

mass of Pendulum M=10 kg

mass of bullet m=5.5 gm

velocity of bullet u

After collision let say velocity is v

conserving momentum we get

$mu=(M+m)v$

$v=\frac{m}{M+m}\times u$

Conserving Energy for Pendulum

Kinetic Energy=Potential Energy

$\frac{(M+m)v^2}{2}=(M+m)gh$

here $h=L(1-\cos \theta )$ from diagram

therefore

$v=\sqrt{2gL(1-\cos \theta )}$

initial velocity in terms of v

$u=\frac{M+m}{m}\times \sqrt{2gL(1-\cos \theta )}$

For first case $\theta =6.8^{\circ}$

$u_1=\frac{M+m_1}{m_1}\times \sqrt{2gL(1-\cos 6.8)}$

for second case $\theta =11.4^{\circ}$

$u_2=\frac{M+m_2}{m_2}\times \sqrt{2gL(1-\cos 11.4)}$

Therefore $\frac{u_1}{u_2}=\frac{\frac{M+m_1}{m_1}\times \sqrt{2gL(1-\cos 6.8)}}{\frac{M+m_2}{m_2}\times \sqrt{2gL(1-\cos 11.4)}}$

$\frac{u_1}{u_2}=\frac{1819.181\times 0.0838}{1001\times 0.1404}$

$\frac{u_1}{u_2}=1.084$

i.e. $\frac{v_1}{v_2}=1.084$

4 0

3 years ago

6.A string of 100 Christmas lights requires 4 Volts and 2 Amps for a single bulb to light up. (a) When one light on the sting go

Molodets [167]

Answer:

Explanation:

From the information given,

V = 4 volts

A = 2 amps

In the first instance, one light on the sting goes out and the whole string of lights no longer turns on. This means that the circuit is a series circuit.

b) Total voltage = 4 x 100 = 400 V

The current passing through each bulb is the same. Thus

Total Current = 2 Amps

Recall, V = IR

R = V/I

Thus,

Resistance = 400/2

Resistance = 200 ohms

c) In this case, one light goes out on the string all other lights still turn on. This means that the circuit is a parallel circuit

The voltage is the same

Total voltage = 4 volts

Total current = 2 x 100 = 200 amps

Total resistance = 4/200

Total resistance = 0.02 ohms

3 0

1 year ago