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.
The figure mentioned on the question is in the attachment.
Answer: a)
= - 38.35N
b)
= 30.5 N
c)
= 27.45 N
d) a = - 13.16 m/s²
Explanation: A block on an inclined plane has 3 forces acting on it:
- Force due to gravity
= m.g; - Normal Force due to the plane;
- Force of Friction
= µ.N;
Since the plane is inclined, Normal Force is equal the y-component of the force due to gravity and Force of friction and the x-component of the force due to gravity are opposite forces.
The second attachment ilustrate the forces acting on the block.
Calculating:
A) The magnitude of the x-component of Force due to gravity:
According to the second image:
= P.sinθ
= 5.9.8.sin(36.8)
= - 38.35 N
B)
=
= m.g.cosθ
= 5.9.8.cos(36.8)
= 30.5 N
C)
= 0.9.30.5
= 27.45 N
D) For the acceleration, use Newton's Law:
= m . a
If there is movement, it is only on x-axis, so the net force is:
-
= m.a
- 38.35 - 27.45 = 5a
a = - 13.16 m/s²
The value of acceleration shows there is <u>no</u> <u>movement</u> on the x-axis due to the friction.
Mass of the car = 1200 kg
Mass of the truck = 2100 kg
Total mass of car and truck = 2100 + 1200 = 3300 kg
Since, the car pushes the truck. Hence, they will move together and will have same acceleration.
Let the acceleration be a.
According to Newton's second law:
F(net) = ma
F = 4500 N
4500 = 3300 × a

a = 1.36 m/s^2
Let the force applied by the car on truck be F.
F = F(net) on the truck
F = ma
F = 2100 × 1.36
F = 2856 N
Hence, the force applied by the car on the truck is 2856 N
Answer:
The tennis ball.
Explanation:
Because the baseball is heavier, it requires more force to move it, whereas the tennis ball requires less force, so it will move more. Hope that makes sense!
The appearance of the organism and its structures, because the fossils are basically worn out parts of the organism. IT IS basically the organism.