When balancing an equation, you can

What causes the apparent motions of stars across the sky each night

densk [106]

Answer:

B

Explanation:

for the motion every night, it is because the Earth spins on its axis.

for the changes over a year, this is because the Earth rotates around the sun.

for the changes over hundreds, thousands or millions of years, this is because the whole solar system (including the Earth, of course) rotates with all the other stars in our galaxy around the center of the galaxy. and each star system has its own orbit (similar to the planets in our solar system).

it is very rare to see objects outside of our galaxy without a telescope, but they change too over a long period of time, because our galaxy not only rotates by also moves through the universe, and these other objects move on their own too.

3 0

3 years ago

For which optical devices does d¡ always have a negative value?

Dmitry [639]

Answer:

Explanation:

A i think

6 0

3 years ago

Read 2 more answers

the force of a bag of potatoes on a vegetable stand is 22.5 N down. what is the force of the vegetable stand on the bag of potat

natima [27]

As per Newton's III law we can say that

Force applied by object 1 on object 2 is always equal in magnitude and opposite in direction of the force that object 2 apply on object 1.

So we can say it as

$F_{12} = -F_{21}$

now here above question is based upon the same

if a bag of vegetables applied a force F = 22.5 N of the surface stand the the same surface will apply same magnitude of force in opposite direction on the vegetables bag

So our answer will be F = 22.5 N (upwards).

4 0

3 years ago

If the mass of the ladder is 12.0 kgkg, the mass of the painter is 55.0 kgkg, and the ladder begins to slip at its base when her

Marysya12 [62]

Answer:

μ = 0.336

Explanation:

We will work on this exercise with the expressions of transactional and rotational equilibrium.

Let's start with rotational balance, for this we set a reference system at the top of the ladder, where it touches the wall and we will assign as positive the anti-clockwise direction of rotation

fr L sin θ - W L / 2 cos θ - W_painter 0.3 L cos θ = 0

fr sin θ - cos θ (W / 2 + 0,3 W_painter) = 0

fr = cotan θ (W / 2 + 0,3 W_painter)

Now let's write the equilibrium translation equation

X axis

F1 - fr = 0

F1 = fr

the friction force has the expression

fr = μ N

Y Axis

N - W - W_painter = 0

N = W + W_painter

we substitute

fr = μ (W + W_painter)

we substitute in the endowment equilibrium equation

μ (W + W_painter) = cotan θ (W / 2 + 0,3 W_painter)

μ = cotan θ (W / 2 + 0,3 W_painter) / (W + W_painter)

we substitute the values they give

μ = cotan θ (12/2 + 0.3 55) / (12 + 55)

μ = cotan θ (22.5 / 67)

μ = cotan tea (0.336)

To finish the problem, we must indicate the angle of the staircase or catcher data to find the angle, if we assume that the angle is tea = 45

cotan 45 = 1 / tan 45 = 1

the result is

μ = 0.336

5 0

4 years ago

Diagram of an atom with labels

lina2011 [118]

See this. I hope you find your answer

6 0

3 years ago