Answer: a) for 150 Angstroms 6.63 *10^-3 eV; b) for 5 Angstroms 6.02 eV
Explanation: To solve this problem we have to use the relationship given by De Broglie as:
λ =p/h where p is the momentum and h the Planck constant
if we consider the energy given by acceleration tube for the electrons given by: E: e ΔV so is equal to kinetic energy of electrons p^2/2m
Finally we have:
eΔV=p^2/2m= h^2/(2*m*λ^2)
replacing we obtained the above values.
Answer:
D.
Explanation:
Given that your boat departs from the bank of a river that has a swift current parallel to its banks. If you want to cross this river in the shortest amount of time, you should direct your boat: so that it drifts with the current.
If the boat moves perpendicular to the current, the current flow will be the resistance to the movement of the boat. So, it's better for the boat to drifts perpendicularly with the current.
The best answer is therefore option D.
Answer:
a = 0.7267
, acceleration is positive therefore the speed is increasing
Explanation:
The definition of acceleration is
a = dv / dt
they give us the function of speed
v = - (t-1) sin (t² / 2)
a = - sin (t²/2) - (t-1) cos (t²/2) 2t / 2
a = - sin (t²/2) - t (t-1) cos (t²/2)
the acceleration for t = 4 s
a = - sin (4²/2) - 4 (4-1) cos (4²/2)
a = -sin 8 - 12 cos 8
remember that the angles are in radians
a = 0.7267
the problem does not indicate the units, but to be correct they must be m/s²
We see that the acceleration is positive therefore the speed is increasing
Im not gonna write for you a whole short story (I don't have time), but just describe what you observed (in a fake reality).
For the relationship between the predator-prey: you could say a snake eating a mouse.
Commenalism: lets say...moss grows on a tree and benefits, but it doesn't hurt or effect the tree.
Mutalism: a bird on a rhino. The bird eats parasites and bugs that feed off the rhino, the bird gets food and the rhino stays clean and parasite free.
Parasitism: a dog and a flea. Only the flea benefits from the dog. The dog has to suffer from the parasites evilness.
Now just thread it together and describe it. Comparing is easy, just use the definition of, for example, commensalism, mutalism, in one relationship, one organism benefits, in the other, both benefit.
Have fun!
