Abundant energy: Fusing atoms together in a controlled way releases nearly four million times more energy than a chemical reaction such as the burning of coal, oil or gas and four times as much as nuclear fission reactions (at equal mass)
Answer:
The final speed of the crate is 12.07 m/s.
Explanation:
For the first 10.0 meters, the only force acting on the crate is 225 N, so we can calculate the acceleration as follows:
Now, we can calculate the final speed of the crate at the end of 10.0 m:
For the next 10.5 meters we have frictional force:
So, the acceleration is:
The final speed of the crate at the end of 10.0 m will be the initial speed of the following 10.5 meters, so:
Therefore, the final speed of the crate after being pulled these 20.5 meters is 12.07 m/s.
I hope it helps you!
The Pony Express
Chapter 1
At A Nation's Crisis
The Pony Express was the first rapid transit and the first fost mail line across the continent from the Missouri River to the Pacific Coast. It was a system
by means of which messages were carried swiftly on horseback across the plains and deserts, and over the mountains of the far West It brought the
Adontic coost and the Pacific slope ten days nearer to each other.
It had a brief existence of only sixteen months and was supplanted by the transcontinental telegraph. Yet it was of the greatest importance in
binding the East and West together at a time when overland travel was slow and cumbersome, and when a great national crisis made the rapid
communication of news between these sections an imperative necessity.
The Pony Express marked the highest development in overland travel prior to the coming of the Pacific railroad, which it preceded nine years.
It, in fact, proved the feasibility of a transcontinental road and demonstrated that such a line could be built and operated continuously the year
around-a feat that had always been regarded as impossible.
The operation of the Pony Express was a supreme achievement of physical endurance on the part of man and his ever faithful companion, the
horse. The history of this organization should be a lasting monument to the physical sacrifice of man and beast in an effort to accomplish
something worthwhile. Its history should be an enduring tribute to American courage and American organizing genius.
Read this line from the Pony Express excerpt
It hod a brief existence of only sixteen months and was supplanted by the transcontinental telegraph.
Based on the corres, what does the word "supplanted" mean? (5 points)
Defeated
Joined
Replaced
Os
Oo
Unearthed
Answer:
In an elastic collision:
- There is no external net force acting. Thus, Momentum before and after collision is equal. Momentum remains conserved.
- Total energy always remains conserved as energy cannot be created nor destroyed. It can change from one form to another.
- There is no lost due to friction in elastic collision. So the kinetic energy is also conserved.
- Velocities may change after collision. If the masses are equal, the velocities interchange.
When one object is stationary:
Final velocity of object 1:
v₁ = (m₁ - m₂)u₁/(m₁ +m₂)
Final velocity of object 2:
v₂ = (2 m₁ u₁)/(m₁+m₂) =
- Objects do not stick together in elastic collision. They stick together in inelastic collision.
- One object may be stationary before the elastic collision.
Thus, conditions for an elastic collision:
- Energy is conserved.
- Velocities may change.
- Momentum is conserved.
- Kinetic energy is conserved.
- One object may be stationary before the elastic collision.
Not that we know of today, but we didn't know about dark matter until a few years ago.
