⁻Answer:
Ne=1.8 *10^37
Explanation:
Current density J=Iₐ /(πr²)
= 8/(π* (1.5*10⁻³/2)²)= 4.53*10⁶ A/m²
Drift velocity = J/ne =4.53*10⁶ /(8.5×1028 *1.6×10−19 ) = 3.33 ×10−4 m/s
volume = πr²h= π * (1.5*10⁻³/2)² * 3 = 5.3 ×10−6 m³
Ne=1.8 *10^37
Complete question:
The recoil of a shotgun can be significant. Suppose a 3.6-kg shotgun is held tightly by an arm and shoulder with a combined mass of 15.0 kg. When the gun fires a projectile with a mass of 0.040 kg and a speed of 380 m/s, what is the recoil velocity of the shotgun and arm–shoulder combination?
Answer:
The recoil velocity of the shotgun and arm–shoulder combination is 1.013 m/s
Explanation:
Given;
combined mass of the shotgun and arm–shoulder, m₁ = 15 kg
mass of the projectile, m₂ = 0.04 kg
speed of the projectile, u₂ = 380 m/s
let the recoil velocity of the shotgun and arm–shoulder combination = u₁
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = 0
m₁u₁ = - m₂u₂
Therefore, the recoil velocity of the shotgun and arm–shoulder combination is 1.013 m/s
Answer options:
A) Some connections are lost because critical stages of development were missed.
B) Some connections are lost so others can be strengthened.
C) Some connections are lost because of experimentation with drugs or alcohol.
D) Some connections are lost so that children become less dependent and are less tied to their parents.
Answer:
B) Some connections are lost so others can be strengthened.
Explanation:
Synaptic pruning refers to a natural process that occurs in the brain between childhood and adulthood. Extra synaptic connections are eliminated in order to increase the efficiency of neuronal communications. It is thought to be the brain’s way of removing connections that are no longer needed.
Try this suggested solution; note, the answers are underlined with red colour.