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3 years ago

Pick a common happening , develop an explanation for it , and describe an experiment you could perform to test your explanation.

1 answer:

5 0

Plant's produce oxygen, to explain this you would state that the plant uses CO2 from the air and removes the carbon and then release breathable O2 into the atmosphere. To test this you could use a small fern and put it in a sealed container of some kind big enough to hold it, then add a burning candle in the container with the plant, since we know fire burms O2 and creates CO2 the plant should use the CO2 and create more O2 keeping the fire from burning out from lack of oxygen

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A small rubber ball is launched by a compressed-air cannon from ground level with an initial speed of 17.3 m/s directly upward.

elena-s [515]

Answer:

h=15.27m

Explanation:

Since at maximum height the vertical velocity must be null it's better to use the formula:

$v_f^2=v_i^2+2ad$

We will use this formula for the vertical direction, choosing the upward direction as the positive one, so we have:

$0=v_i^2+2ah$

$h=-\frac{v_i^2}{2a}$

which for our values is:

$h=-\frac{(17.3m/s)^2}{2(-9.8m/s^2)}=15.27m$

7 0

3 years ago

You hang a heavy ball with a mass of 10 kg from a gold wire 2.6 m long that is 1.6 mm in diameter. You measure the stretch of th

PolarNik [594]

Answer: The Young's modulus for the wire is $6.378\times 10^{10}N/m^2$

Explanation:

Young's Modulus is defined as the ratio of stress acting on a substance to the amount of strain produced.

The equation representing Young's Modulus is:

$Y=\frac{F/A}{\Delta l/l}=\frac{Fl}{A\Delta l}$

where,

Y = Young's Modulus

F = force exerted by the weight = $m\times g$

m = mass of the ball = 10 kg

g = acceleration due to gravity = $9.81m/s^2$

l = length of wire = 2.6 m

A = area of cross section = $\pi r^2$

r = radius of the wire = $\frac{d}{2}=\frac{1.6mm}{2}=0.8mm=8\times 10^{-4}m$ (Conversion factor: 1 m = 1000 mm)

$\Delta l$ = change in length = 1.99 mm = $1.99\times 10^{-3}m$

Putting values in above equation, we get:

$Y=\frac{10\times 9.81\times 2.6}{(3.14\times (8\times 10^{-4})^2)\times 1.99\times 10^{-3}}\\\\Y=6.378\times 10^{10}N/m^2$

Hence, the Young's modulus for the wire is $6.378\times 10^{10}N/m^2$

3 0

3 years ago

When working with a powered instrument, the swirling effect produced by the water stream within the confined space of a periodon

Lina20 [59]

Answer:

Acoustic microstreaming

Explanation:

Acoustic microstreaming is the swirling effect produced by water stream confined in a spaced of a periodontal pocket.

It is the movement of water in a particular direction as a result of mechanical pressure within the fluid body.
They are often used in dental procedures to remove particulates from the teeth.
It mostly relies on the properties of sound waves to achieve this goal

3 0

3 years ago

Consider an electron with charge −e and mass m orbiting in a circle around a hydrogen nucleus (a single proton) with charge +e.

alexandr1967 [171]

Answer:

$v=\sqrt{k\frac{e^2}{m_e r}}$ , $2.18\cdot 10^6 m/s$