F = 130 revs/min = 130/60 revs/s = 13/6 revs/s
t = 31s
wi = 2πf = 2π × 13/6 = 13π/3 rads/s
wf = 0 rads/s = wi + at
a = -wi/t = -13π/3 × 1/31 = -13π/93 rads/s²
wf² - wi² = 2a∅
-169π²/9 rads²/s² = 2 × -13π/93 rads/s² × ∅
∅ = 1209π/18 rads
n = ∅/2π = (1209π/18)/(2π) = 1209/36 ≈ 33.5833 revolutions.
1) describe the life cycle of a star before it collapses into a black hole.
1) describe the life cycle of a star before it collapses into a black hole.ans: A star's life cycle is determined by its mass. The larger its mass, the shorter its life cycle. A star's mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born. Over time, the hydrogen gas in the nebula is pulled together by gravity and it begins to spin. As the gas spins faster, it heats up and becomes as a protostar. Eventually the temperature reaches 15,000,000 degrees and nuclear fusion occurs in the cloud's core. The cloud begins to glow brightly, contracts a little, and becomes stable. It is now a main sequence star and will remain in this stage, shining for millions to billions of years to come. This is the stage our Sun is at right now.
2) describe the life cycle of a star before it becomes a dwarf.
ans: The life cycle of a low mass star (left oval) and a high mass star (right oval). ... As the core collapses, the outer layers of the star are expelled. A planetary nebula is formed by the outer layers. The core remains as a white dwarf and eventually cools to become a black dwarf.
3) what is the likely outcome of our sun?
ans: All stars die, and eventually — in about 5 billion years — our sun will, too. Once its supply of hydrogen is exhausted, the final, dramatic stages of its life will unfold, as our host star expands to become a red giant and then tears its body to pieces to condense into a white dwarf.
Detergents are special, powerful cleansers that can break up dirt, oils, and grease in clothing or on dishes.
Cleaning solvents are used to remove oil, grease, solder flux, and other contaminants.
Acid cleaners are generally used to remove mineral deposits and are useful for descaling dishwashers or removing rust from restroom facilities.
Abrasive uses
* Buffing.
* Honing.
* Drilling.
* Grinding.
* Sanding.
* Polishing.
* Cutting.
* Sharpening.
Answer:
The magnitude of the vector sum of A and B is 65.8 cm and its direction 61.6°
Explanation:
Since vector A has magnitude 50 cm and a direction of 30, its x - component is A' = 50cos30 = 43.3 cm and its y - component is A" = 50sin30 = 25.
Also, Since vector B has magnitude 35 cm and a direction of 110, its x - component is A' = 35cos110 = -11.97 cm and its y - component is A" = 35sin110 = 32.89 cm.
So, the vector sum R = A + B
The x-component of the vector sum is R' = A'+ B' = 43.3 cm + (-11.97 cm) = 43.3 cm - 11.97 cm = 31.33 cm
The y-component of the vector sum is R" = A"+ B" = 25 cm + 32.89 cm = 57.89 cm
So, the magnitude of R = √(R'² + R"²)
= √((31.33 cm)² + (57.89 cm)²)
= √(981.5689 cm² + 3,351.2521 cm²)
= √(4,332.821 cm²)
= 65.82 cm
≅ 65.8 cm
The direction of R is Ф = tan⁻¹(R"/R')
= tan⁻¹(57.89 cm/31.33 cm)
= tan⁻¹(1.84775)
= 61.58°
≅ 61.6°
So, the magnitude of the vector sum of A and B is 65.8 cm and its direction 61.6°
Answer:
a = -1 m/s^2
Explanation:
Vi = 75 m/s
Vf = 25 m/s
t = 50 s
Plug those values into the following equation:
Vf = Vi + at
25 = 75 + 50a
---> a = -1 m/s^2
