Answer:
Explanation:
Bohr's energy expression is as follows
E_n = 13.6 z² /n² where z is atomic no and n is principal quantum no of the atom .
z for helium is 2 and for ionised atom is 5 . Let energy of n₁ level of He is equal to energy level n₂ of ionised atom
so
13.6 x 2² / n₁² = 13.6 x 5² / n₂²
n₁ / n₂ = 2/5 , ie 2nd energy level of He matches 5 th energy level of ionised atom .
For quantum numbers less than or equal to 9 , If we take n₁ = 8 for He
Putting it in the equation above
2² / 8² = 5² / n₂²
n₂ = 5 x 8 / 2
= 20 .
energy
= - 13.6 x2² / 8²
= - 0.85 eV .
Answer: k= 
Explanation:
Recall that the formula for kinetic energy is given below as
k = 
where k=kinetic energy (joules), m= mass of object (kg), v= velocity of object m/s)
For cart A
= mass of cart A
= v = velocity of cart A
= kinetic energy of cart A
hence, = 
For cart B
= mass of cart B
= 2v = velocity of cart B
= kinetic energy of cart B
hence, = 
= 2
from the question, both cart are identical which implies they have the same mass i.e = = m which implies that
and 
The total kinetic energy K is the sum of cart A and cart B kinetic energy
hence
Kinetic energy is calculated through the equation,
KE = 0.5mv²
At initial conditions,
m₁: KE = 0.5(0.28 kg)(0.75 m/s)² = 0.07875 J
m₂ : KE = 0.5(0.45 kg)(0 m/s)² = 0 J
Due to the momentum balance,
m₁v₁ + m₂v₂ = (m₁ + m₂)(V)
Substituting the known values,
(0.29 kg)(0.75 m/s) + (0.43 kg)(0 m/s) = (0.28 kg + 0.43 kg)(V)
V = 0.2977 m/s
The kinetic energy is,
KE = (0.5)(0.28 kg + 0.43 kg)(0.2977 m/s)²
KE = 0.03146 J
The difference between the kinetic energies is 0.0473 J.
The force exerted on the car during this stop is 6975N
<u>Explanation:</u>
Given-
Mass, m = 930kg
Speed, s = 56km/hr = 56 X 5/18 m/s = 15m/s
Time, t = 2s
Force, F = ?
F = m X a
F = m X s/t
F = 930 X 15/2
F = 6975N
Therefore, the force exerted on the car during this stop is 6975N
We solve this using special
relativity. Special relativity actually places the relativistic mass to be the
rest mass factored by a constant "gamma". The gamma is equal to 1/sqrt
(1 - (v/c)^2). <span>
We want a ratio of 3000000 to 1, or 3 million to 1.
</span>
<span>Therefore:
3E6 = 1/sqrt (1 - (v/c)^2)
1 - (v/c)^2 = (0.000000333)^2
0.99999999999999 = (v/c)^2
0.99999999999999 = v/c
<span>v= 99.999999999999% of the speed of light ~ speed of light
<span>v = 3 x 10^8 m/s</span></span></span>
