Here are two leading theories to explain how the first galaxies formed. The truth may involve a bit of both ideas.
One says that galaxies were born when vast clouds of gas and dust collapsed under their own gravitational pull, allowing stars to form.
The other, which has gained strength in recent years, says the young universe contained many small "lumps" of matter, which clumped together to form galaxies. Hubble Space Telescope has photographed many such lumps, which may be the precursors to modern galaxies. According to this theory, most of the early large galaxies were spirals. But over time, many spirals merged to form ellipticals.
So, physical properties are what we can detect with our basic 5 senses or measuring tools, and the things that, when changed, dont actually change the chemical properties (like atoms and molecules). Lets take wood for an example: its brown, its solid, it can be big or small, it has a taste and smell, its boiling, freezing or melting point...
Chemical properties, on the other hand, are the things we can change with, for example, experiments and tools. Does it burn? Can it rust/oxidize? How does it react with other chemicals? Is it radioactive, or toxic? All of these are chemical properties you can probably answer.
Answer:
2 m/s².
Explanation:
The forces acting on the crate have been shown in the figure below.
Net force acting on the crate in the horizontal direction = 400 - 250 = 150 N towards right.
For the forces of vertical direction we can write,
Normal force = 150 + Mg = 150 + 250 = 400 N (here g = 10 m/s² have been taken)
The magnitude of frictional force that will act on the crate = μ × Normal force
So, Frictional force = 0.25 × 400 = 100 N
Thus, the net force that will cause acceleration in the crate will be
Force in the right direction - frictional force
= 150 - 100 = 50 N
As we know,
Acceleration =
=
= 2 m/s²
So, the net acceleration in the crate will be 2 m/s².
Blue, blue-white, Yellow-white, yellow, yellow-orange, and red. Hope this helps.