Answer:
Energy of Photon = 4.091 MeV
Explanation:
From the conservation of energy principle, we know that total energy of the system must remain conserved. So, the energy or particles before collision must be equal to the energy of photons after collision.
K.E OF electron + Rest Energy of electron + K.E of positron + Rest Energy of positron = 2(Energy of Photon)
where,
K.E OF electron = 3.58 MeV
Rest Energy of electron = 0.511 MeV
Rest Energy of positron = 0.511 MeV
K.E OF positron = 3.58 MeV
Energy of Photon = ?
Therefore,
3.58 MeV + 0.511 MeV + 3.58 MeV + 0.511 MeV = 2(Energy of Photon)
Energy of Photon = 8.182 MeV/2
<u>Energy of Photon = 4.091 MeV</u>
Answer:
I think is D I'm sorry if I'm wrong
This question can be solved using the concept of friction energy.
The thermal energy change is b "258.4 J".
The change in thermal energy will be equal to the friction energy produced during the motion of the box.

where,
μ = coefficient of kinetic friction = 0.4
f = force applied = 38 N
d = distance traveled by the box = 17 m
Therefore,

<u>E = 258.4 J</u>
Learn more about friction energy here:
brainly.com/question/1343045?referrer=searchResults
1) 29.4 N
The force of gravity between two objects is given by:

where
G is the gravitational constant
M and m are the masses of the two objects
r is the separation between the centres of mass of the two objects
In this problem, we have
(mass of the Earth)
(mass of the box)
(Earth's radius, which is also the distance between the centres of mass of the two objects, since the box is located at Earth's surface)
Substituting into the equation, we find F:

2) 
Let's now calculate the ratio F/m. We have:
F = 29.4 N
m = 3.0 kg
Subsituting, we find

This is called acceleration of gravity, and it is the acceleration at which every object falls near the Earth's surface. It is indicated with the symbol
.
We can prove that this is the acceleration of the object: in fact, according to Newton's second law,

where a is the acceleration of the object. Re-arranging,

which is exactly equal to the quantity we have calculated above.