If the discovery of oxygen wasn’t made in 1774, do you think it would have been discovered later on?

A scientist mixes an unknown powder into a beaker of water. He then uses an indicator and finds that the pH of the resulting sol

zaharov [31]

A ph higher than 7 is basic so you can eliminate a. The indicator can be used to measure both acids and bases so you can eliminate c. Hydrogen ions are from acids, so the answer is that the powder decreased the hydrogen ions in the water.

7 0

4 years ago

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2000, the Millennium Bridge, a new footbridge over the River Thames in London, England, was opened to the public. However, after

sweet [91]

Answer:

n = 1810

A = 25 mm

Explanation:

Given:

Lateral force amplitude, F = 25 N

Frequency, f = 1 Hz

mass of the bridge, m = 2000 kg/m

Span, L = 144 m

Amplitude of the oscillation, A = 75 mm = 0.075 m

time, t = 6T

now,

Amplitude as a function of time is given as:

$A(t)=A_oe^{\frac{-bt}{2m}}$

or amplitude for unforce oscillation

$\frac{A_o}{e}=A_oe^{\frac{-b(6T)}{2m}}$

or

$\frac{6bt}{2m}=1$

or

$b=\frac{m}{3T}$

Now, provided in the question Amplitude of the driven oscillation

$A=\frac{F_{max}}{\sqrt{(k-m\omega_d^2)+(b\omega_d^2)}}$

the value of the maximum amplitude is obtained $(k=m\omega_d^2)$

thus,

$A=\frac{F_{max}}{(b\omega_d}$

Now, for n people on the bridge

Fmax = nF

thus,

max amplitude

$0.075=\frac{nF}{((\frac{m}{3T})2\pi}$

or

n = 1810

hence, there were 1810 people on the bridge

b) $A=\frac{F_{max}}{(b\omega_d}$

since the effect of damping in the millenium bridge is 3 times

thus,

b=3b

therefore,

$A=\frac{F_{max}}{(3b\omega_d}$

or

$A=\frac{1}{(3}A_o$

or

$A=\frac{1}{(3}0.075$

or

A = 0.025 m = 25 mm

6 0

3 years ago

Select all of the examples of a base.

Degger [83]

Ammonia, Bananas, Bleach,
Tomatoes, Baking Soda are all examples of a base.

8 0

4 years ago

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suppose you are designing a device to transmit information without wires what part of the EM spectrum will your device use and w

miv72 [106K]

My device will use either radio waves or light waves.
Those are the only EM waves I'm equipped to generate.

If I want to get elegant about it, I may use radio waves with
frequencies around 14.1 MHz, because those can be received
many thousands of miles away. I know how to build an effective
antenna to radiate at that frequency, and as a licensed ham-radio
operator, I can do it legally.

5 0

4 years ago

Consider a car moving with a constant velocity of 90 m/s. What is it’s acceleration.

Troyanec [42]

Answer:

Zero

Explanation:

Acceleration is rate of change of velocity..

5 0

4 years ago

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