Answer:
A) 580m
B) 0 m/s
C) 9.8m/s^2
D) downward
E) 10.87s
F) 106.62 m/s
Explanation:
A) The distance traveled by the rocket is calculated by using the following expression:
a: acceleration of the rocket = 2.90 m/s^2
t: time of the flight = 20.0 s
B) In the highest point the rocket has a velocity with magnitude zero v = 0m/s because there the rocket stops.
C) The engines of the rocket suddenly fails in the highest point. There, the acceleration of the rocket is due to the gravitational force, that is 9.8 m/s^2
D) The acceleration points downward
E) The time the rocket takes to return to the ground is given by:
10.87 seconds
F) The velocity just before the rocket arrives to the ground is:
Answer:
72,300 years.
Explanation:
- Initial mass of this sample: 504 grams;
- Current mass of this sample: 63 grams.
What's the ratio between the current and the initial mass of this sample? In other words, what fraction of the initial sample hasn't yet decayed?
.
The value of this fraction starts at 1 decreases to 1/2 of its initial value after every half-life. How many times shall 1/2 be multiplied to 1 before reaching 1/8? 
. It takes three half-lives or 
years to reach that value.
In certain questions the denominator of the fraction is large. It might not even be an integer power of 2. The base-x logarithm function on calculators could help. Evaluate
to find the number of half-lives required. In case the base-x logarithm function isn't available, but the natural logarithm function 
is, apply the following expression (derived from the base-changing formula) to get the same result:
.
Answer: Option (c) is the correct answer.
Explanation:
When two or more small nuclei combine together to form a larger nuclei then this process is known as nuclear reaction.
The smaller is an atom, the more energy it requires to release an electron. This energy is known as binding energy.
Thus, when two small nuclei fuse together then there will be more binding energy as compared to when two large nuclei fuse together.
For example, fusion of two hydrogen atoms release more energy then one helium atom, and upon binding excess energy is released into the space.
Hence, we can conclude that energy is released in a nuclear fusion reaction based on mass-energy equivalence because for small nuclei, the binding energy of the lighter nuclei is greater than the binding energy of the heavier nucleus.
Explanation:
Khi một hạt thực hiện SHM Đang chuyển động từ vị trí cực biên về vị trí trung bình, thì vận tốc và gia tốc cùng hướng, tức là hướng về vị trí trung bình
