Hi there!
We can begin by calculating the distance remaining after the reaction time.
Δd = vt
Calculate the distance traveled within this time:
Δd = (16)(.79) = 12.64 m
Subtract from the total distance:
150 - 12.64 = 137.66 m remaining
We can use the following equation to solve for the acceleration necessary:
vf² = vi² + 2ad, where vf = 0 since the train will have slowed down to rest.
Rearrange in terms of "a":
0 = vi² + 2ad
(-vi²) = 2ad
(-vi²)/2d = a
Plug in the given values:
(-(16²))/2(137.66) = a
-256/275.32 = -.9298 m/s²
1. Mass number of Lithium-7: 7
Explanation:
- The atomic number of an element is equal to the number of protons inside its nucleus
- The mass number of an element is equal to the number of protons+neutrons inside its nucleus
The nomenclature "Element-X", where X is the number of protons+neutrons, is used to indicate the mass number of the isotope. Therefore, an isotope of LIthium-7 has a mass number of 7.
2. An isotope of lithium-8 contains 5 neutrons
Explanation:
Lithium is the third element of the periodic table, so its atomic number is 3, which means that it has 3 protons.
In this problem, we have an isotope of lithium-8, which means that it has a mass number of 8: so, the sum of neutrons+protons in its nucleus is 8:
where p is the number of protons and n the number of neutrons. However, we also know that for lithium p=3, so we can find the number of neutrons:
Answer:
28.8 cm
Explanation:
Magnification in a microscope is:
M = Mo * Me
Where
Mo: magnification of the objective,
Me: Magnification of the eyepiece.
The magnification of the objective if:
Me = npd/fe
Where:
npd: near point distance
fe: focal length of the eyepiece
The magnification of the objective:
Mo = d/fo
Where
d: the distance between lenses
fo: focal length of the objective
Then
M = npd/fe * d/fo
d = M * fe * fo / npd
d = 12 * 5 * 12 / 25 = 28.8 cm
There are <span>31,556,736 seconds in a solar year.</span>
Answer:
ΔT = 1ºC
, 2ºCand 3ºC
Explanation:
In this exercise they indicate the specific heat of lithium
let's calculate the temperature increase as a function of the heat introduced
Q = m ΔT
ΔT = Q / m c_{e}
calculate
for Q = 3.5 J
ΔT = 3.5 / (1 3.5)
ΔT = 1ºC
For Q = 7.0 J
ΔT = 7 / (1 3.5)
ΔT = 2ºC
for Q = 10.5 J
ΔD = 10.5 / (1 3.5)
ΔT = 3ºC
we see that this is a straight line, see attached