Answer:
Broglie wavelength: electron 1.22 10⁻¹⁰ m
, proton 2.87 10⁻¹² m
, hydrogen atom 7.74 10⁻¹² m
Explanation:
The equation given by Broglie relates the momentum of a particle with its wavelength.
p = h /λ
In addition, kinetic energy is related to the amount of movement
E = ½ m v²
p = mv
E = ½ p² / m
p = √2mE
If we clear the first equation and replace we have left
λ = h / p =
λ = h / √2mE
Let's reduce the values that give us SI units
1 ev = 1,602 10⁻¹⁹ J
E1 = 100 eV (1.6 10⁻¹⁹ J / 1eV) = 1.6 10⁻¹⁷ J
We look in tables for the mass of the particle and the Planck constant
h = 6,626 10-34 Js
me = 9.1 10-31 Kg
mp = 1.67 10-27 Kg
Now let's replace and calculate the wavelengths
a) Electron
λ1 = 6.6 10⁻³⁴ / √(2 9.1 10⁻³¹ 1.6 10⁻¹⁷) = 6.6 10⁻³⁴ / 5.39 10⁻²⁴
λ1 = 1.22 10⁻¹⁰ m
b) Proton
λ2 = 6.6 10-34 / √(2 1.67 10⁻²⁷ 1.6 10⁻¹⁷) = 6.6 10⁻³⁴ / 2.3 10⁻²²
λ2 = 2.87 10⁻¹² m
c) Bohr's first orbit
En = 13.606 / n2 [eV]
n = 1
E1 = 13.606 eV
E1 = 13,606 ev (1.6 10⁻¹⁹ / 1eV) = 21.77 10⁻¹⁹ J
λ3 = 6.6 10⁻³⁴ /√(2 1.67 10⁻²⁷ 21.77 10⁻¹⁹) = 6.6 10⁻³⁴ / 8.52 10⁻²³
λ3 = 0.774 10⁻¹¹ m = 7.74 10⁻¹² m
Answer:
2.5 m/s²
Explanation:
Using the formula, v = u + at ( v = Final velocity; u = Initial velocity; t = Time; a = Acceleration)
25 = 0 + 10a
a = 25/10 = 2.5 m/s²
Answer:
In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration. In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction
The initial kinetic energy of the boat and its rider is
After Sam stops it, the final kinetic energy of the boat+rider is
because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:
where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.