Atomic numbers for atoms _____ in increments of _____ as you move across the periodic table of elements

The drawings show three examples of the force with which someone pushes against a vertical wall. In each case the magnitude of t

Monica [59]

Complete Question

The complete question is shown on the

Answer:

The ascending order would be 2nd < 1st < 3rd

Explanation:

Generally the the Normal force is mathematically represented as

$Normal \ Force = Fsin \theta$

=> $Normal \ Force \ \alpha \ sin \theta$

For the first drawing the value $\theta$ is between that of the the second and the third drawing so the Normal force would also be between the normal forces of the second and the third drawing

For the second drawing whose value of $\theta$ is less than that of the first and the third the normal force would also be less than that of the first and third

For the the third drawing whose value is (90°) which is higher than the first and the second the normal force would also be higher than the first and the second

4 0

2 years ago

Read 2 more answers

Two paths lead to the top of a big hill. One is steep and direct, while the other is twice as long but less steep. How much more

umka2103 [35]

Answer:

None.

Explanation:

Gravitational potential energy, depends only of the mass on which the gravity is doing work, and the displacement produced by this force.
As displacement depends only on the final and initial positions (in this case, the height of the hill), if we choose as our zero reference level the bottom of the hill, the change in gravitational potential energy will be as follows:

$\Delta U = U_{f} -U_{0} = m*g*h - 0 = m*g*h$

As we can see, the only value of distance involved is the height of the hill , so it is independent of the distance travelled.

6 0

3 years ago

Halleys comet has period of 75.3 years. Using Kepler’s third law, find it’s semimajor axis expressed in astronomical units?

natta225 [31]

Answer: 17.83 AU

Explanation:

According to Kepler’s Third Law of Planetary motion “The square of the orbital period of a planet is proportional to the cube of the semi-major axis (size) of its orbit”. 

$T^{2}\propto a^{3}$ (1)

Talking in general, this law states a relation between the orbital period $T$ of a body (moon, planet, satellite, comet) orbiting a greater body in space with the size $a$ of its orbit.

However, if $T$ is measured in years, and $a$ is measured in astronomical units (equivalent to the distance between the Sun and the Earth: $1AU=1.5(10)^{8}km$ ), equation (1) becomes:

$T^{2}=a^{3}$ (2)

This means that now both sides of the equation are equal.

Knowing $T=75.3years$ and isolating $a$ from (2):

$a=\sqrt[3]{T^{2}}=T^{2/3}$ (3)

$a=(75.3years)^{2/3}$ (4)

Finally:

$a=17.83AU$ (5)

4 0

2 years ago

One end of a horizontal spring with force constant 130.0 Ni'm is attached to a vertical wall. A 4.00-kg block sitting on the flo

tekilochka [14]

Answer:

Explanation:

When the spring is compressed by .80 m , restoring force by spring on block

= 130 x .80

= 104 N , acting away from wall

External force = 82 N , acting towards wall

Force of friction acting towards wall = μmg

= .4 x 4 x 9.8

= 15.68 N

Net force away from wall

= 104 -15.68 - 82

= 6.32 N

Acceleration

= 6.32 / 4

= 1.58 m / s²

It will be away from wall

Energy released by compressed spring = 1/2 k x²

= .5 x 130 x .8²

= 41.6 J

Energy lost in friction

= μmg x .8

= .4 x 4 x 9.8 x .8

= 12.544 J

Energy available to block

= 41.6 - 12.544 J

= 29 J

Kinetic energy of block = 29

1/2 x 4 x v² = 29

v = 3.8 m / s

This will b speed of block as soon as spring relaxes. (x = 0 )

4 0

3 years ago

What evidence supports the ages of our planets, moon, sun, and asteroids

Pie

It is indeed true that scientists have known about the background radiation (commonly known as the Cosmic Microwave Background) since the early 60s. It was first discovered quite by accident by Penzias and Wilson working at Bell Labs, who detected it as an unexplainable interference in their precision radio equipment. When people finally figured out exactly what it was they were seeing, they won the Nobel Prize for their discovery. Only a few years before, George Gamow had predicted that if the Big Bang theory were correct, we should observe just such a background radiation. The CMB is not the only evidence in favor of the Big Bang, but it is one of the most important. It is a natural consequence of the theory, and is pretty unexplainable in steady-state cosmology.

The 15-20 billion year number comes not from the CMB, but rather predominantly from measurements of nearby and distant galaxies, particularly their rates of expansion away from us. We find that the distance to a galaxy is proportional to its recessional velocity. The constant of proportionality is the Hubble Constant, H, which turns out to be (approximately) the reciprocal of the age of the universe. So we measure the age by measuring recessional velocities. T = 1/H is only true, however, if the universe is not significantly accelerating or decelerating its expansion rate. If the rate of expansion is rapidly accelerating, the universe may be older than 1/H = 15 billion years, give or take. Such an acceleration would be caused by a large value of the Cosmological Constant, a sort of anti-gravity force predicted by General Relativity. There is some evidence that this might be the case.

So finally, yes, the age of the universe, being based on the empirical determination of H, is based on the observed evidence.

6 0

3 years ago