Answer:
a) distance d = 293.36ft
b) acceleration a = 14.67ft/s^2
Explanation:
Acceleration is the change in velocity per unit time.
a = ∆v/t ....1
Given;
Initial velocity vi = 30mph × 5280ft/mile × 1/3600s/h
vi = 44ft/s
Final velocity vf = 70mph × 5280ft/mile × 1/3600s/h
vf = 102.67ft/s
time = 4.0s
From equation 1, acceleration is;
a = ∆v/t = (102.67-44)/4 = 14.67ft/s^2
Distance travelled can be given as;
d = ut + 0.5at^2 .....2
u = 44ft/s
t = 4
a = 14.67ft/s^2
Substituting into the equation 2
d = 44(4) + 0.5(14.67×4^2)
d = 293.36ft
I think it’s true I may be wrong tho
Answer:
B. 14
Explanation:
For an element:
- Atomic number: is the number of protons in the nucleus (p)
- Mass number: it is the number of protons (p) + neutrons (n) in the nucleus
For Al (aluminium), we have:
p = 13
p + n = 27
Substituting the first equation into the second one, we find the number of neutrons:
n = 27 - p = 27 - 13 = 14
One of the last two answers
Answer:
a) λ = 121.5 nm
, b) 102.6, 97, 91.1 nm
Explanation:
Bohr's model describes the energy of the hydrogen atom
= k² e² / 2m (1 / n²)
A transition occurs when the electron passes from n level to a lower one
-
= k² e² / 2m (1 /
² - 1 /
²)
Planck's relationship is
E = h f = h c / lam
hc /λ = k² e²/ 2m(1 /
² - 1 /
²)
1 / λ = [k² e² / 2m h c] (1 /
² - 1 /
²)
1 /λ = Ry] (1 /
² - 1 /
²)
a) the first element of the series occurs for
= 2
1 / λ = 1.097 10⁷ (1- 1/2²)
1 / λ = 1.097 10⁷ (1- 0.25)
1 / λ = 0.82275 10⁷
λ = 1.215 10⁻⁷ m
λ = 1,215 10⁻⁷ m (10⁹nm / m)
λ = 121.5 nm
b) the next elements of the series occur to
1 /λ λ (10-7m) λ (nm)
3 1 1,097 10⁷ (1-1 / 9) 1,0255 102.6
4 1 1,097 10⁷ (1-1 / 16) 0.9723 97.2
∞ 1 1,097 10⁷ (1 - 0) 0.91158 91.1