Answer:
For Total energy and momentum to be conserved, the minimum energy of the photons released is equal to twice the rest mass energy of an electron that is 
The annihilation of electron -positron cannot produce a single photon. It is prohibited by the law of conservation of energy and momentum.
Answer:
1.11 s.
Explanation:
From the question given above, the following data were obtained:
Height (H) = 6 m
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =.?
The time taken for the branch to hit the ground can be obtained as follow:
H = ½gt²
6 = ½ × 9.8 × t²
6 = 4.9 × t²
Divide both side by 4.9
t² = 6/4.9
Take the square root of both side
t = √(6/4.9)
t = 1.11 s
Therefore, it will take 1.11 s for the branch to hit the ground.
Answer:
1.63 
Explanation:
The equation
would be used where:
g = acceleration due to gravity
G = universal gravitational constant (6.67408 ×
)
M = mass
R = radius.
assuming the values following both 10s of the mass and radius are their exponents, which is a little confusing, the values given would simply be substituted.
Anyone can correct me if I'm wrong.
Hope this helps you! This is my step-by-step work. Lemme know if you have any questions!