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.
I am not sure but i think the answer is C
Answer:
E = 1440 kJ
Explanation:
It is given that,
Power of a cooker oven is 800 W
Voltage at which it is operated is 230 V
Time, t = 30 minutes = 1800 seconds
We need to find the electrical energy used by the cooker oven. The product of power and time is equal to the energy consumed. So,
So, electrical energy of 1440 kJ is consumed by the cooker oven.
Answer:
The sound travelled 516 meters before bouncing off a cliff.
Explanation:
The sound is an example of mechanical wave, which means that it needs a medium to propagate itself at constant speed. The time needed to hear the echo is equal to twice the height of the canyon divided by the velocity of sound. In addition, the speed of sound through the air at a temperature of 20 ºC is approximately 344 meters per second. Then, the height of the canyon can be derived from the following kinematic formula:
(1)
Where:
- Height, measured in meters.
- Velocity of sound, measured in meters per second.
- Time, measured in seconds.
If we know that 
and 
, then the height of the canyon is:
The sound travelled 516 meters before bouncing off a cliff.
