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3 years ago

PLS ANSWER FAST WILL GIVE BRAINLEST!!!

Physics

1 answer:

Tanya [424]3 years ago

3 0

Answer:

F = 12 N

Explanation:

F = m × a

F = 3 × 4

F = 12 kg m/s²

F = 12 N

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Take one jar with salt water and another with pure water .put an egg into both jars. In which the jar egg floated over the liqui

DanielleElmas [232]

Answer:

if the which coduct salt has more density so the egg floats .

Explanation:

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3 years ago

A researcher is interested in exploring the effects of exposure to ultraviolet light on people’s emotional state. He divides his

bekas [8.4K]

Answer:

Explanation:

In an experimental research, the control group is the group that serves as the neutral group that is not given any form of treatment and serves as the group in which the experimental groups are firstly compared to. Thus, <u>the control group in the question described is the Third group</u>.

While experimental groups are the groups that receive treatments required to make an inference from the experiment. From this description, <u>it can be deduced that the First and the Second group are the experimental groups.</u>

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3 years ago

An open 1-m-diameter tank contains water at a depth of 0.7 m when at rest. As the tank is rotated about its vertical axis the ce

Mamont248 [21]

Answer:

Explanation:

To find the angular velocity of the tank at which the bottom of the tank is exposed

From the information given:

At rest, the initial volume of the tank is:

$V_i = \pi R^2 h_i --- (1)$

where;

height h which is the height for the free surface in a rotating tank is expressed as:

$h = \dfrac{\omega^2 r^2}{2g} + C$

at the bottom surface of the tank;

r = 0, h = 0

∴

$h = \dfrac{\omega^2 r^2}{2g} + C$

0 = 0 + C

C = 0

Thus; the free surface height in a rotating tank is:

$h=\dfrac{\omega^2 r^2}{2g} --- (2)$

Now; the volume of the water when the tank is rotating is:

dV = 2π × r × h × dr

Taking the integral on both sides;

$\int \limits ^{V_f}_{0} \ dV = \int \limits ^R_0 \times 2 \pi \times r \times h \ dr$

replacing the value of h in equation (2); we have:

$V_f} = \int \limits ^R_0 \times 2 \pi \times r \times ( \dfrac{\omega ^2 r^2}{2g} ) \ dr$

$V_f = \dfrac{ \pi \omega ^2}{g} \int \limits ^R_0 \ r^3 \ dr$

$V_f = \dfrac{ \pi \omega ^2}{g} \Big [ \dfrac{r^4}{4} \Big]^R_0$

$V_f = \dfrac{ \pi \omega ^2}{g} \Big [ \dfrac{R^4}{4} \Big] --- (3)$

Since the volume of the water when it is at rest and when the angular speed rotates at an angular speed is equal.

Then $V_f = V_i$

Replacing equation (1) and (3)

$\dfrac{\pi \omega^2}{g}( \dfrac{R^4}{4}) = \pi R^2 h_i$

$\omega^2 = \dfrac{4g \times h_i }{R^2}$

$\omega =\sqrt{ \dfrac{4g \times h_i }{R^2}}$

$\omega = \sqrt{\dfrac{4 \times 9.81 \ m/s^2 \times 0.7 \ m}{(0.5)^2} }$

$\omega = \sqrt{109.87 }$

$\mathbf{\omega = 10.48 \ rad/s}$

Finally, the angular velocity of the tank at which the bottom of the tank is exposed = 10.48 rad/s

6 0

3 years ago

Find your mass if a scale on earth reads 650 N when you stand on it.

netineya [11]

Weight = (mass) x (gravity)

Acceleration of gravity on Earth = 9.8 m/s²

   Weight on Earth = (mass) x (9.8 m/s²)

Divide each side by (9.8 m/s²): Mass = (weight) / (9.8 m/s²)

    Mass = (650 N) / (9.8 m/s²)

   Mass = 66.33 kg (rounded)

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4 years ago

The element magnesium has 2 valence electrons. What is the most likely charge on a magnesium ion?

RSB [31]

The charge is 2+

good luck

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3 years ago