Answer:
They can generate potentials spontaneously because they have Unstable Membrane Potentials.
Explanation:
Autorythmic cells or Pacemaker cells are cells that provide Action potentials (electrical impulses) that starts off the cardiac cycle.
N:B This action potential is created spontaneously.
To explain further, the heart originate in specialized cardiac muscle cells, called autorhythmic cells, that can excite themselves and therefore are able to generate an action potential without external stimulation by nerve cells. And this sets the cardiac cycle i
(Pumping of the heart) into motion. (The pace maker potential)
The Autorhythmic cells create an action potential spontaneously
And this is possible because they have an UNSTABLE RESTING POTENTIAL that is continuously depolarizing, while it drifts slowly toward threshold. As Na+ ions enter the cell, the inner surface of the plasma membrane becomes less negative gradually, thus generating the pacemaker potential.
Answer:
v₀ = 280.6 m / s
Explanation:
we have the shock between the bullet and the block that we can work with at the moment and another part where the assembly (bullet + block) compresses a spring, which we can work with mechanical energy,
We write the mechanical energy when the shock has passed the bodies
Em₀ = K = ½ (m + M) v²
We write the mechanical energy when the spring is in maximum compression

½ (m + M) v² = ½ k x²
Let's calculate the system speed
v = √ [k x² / (m + M)]
v = √[152 ×0.78² / (0.012 +0.109) ]
v = 27.65 m / s
This is the speed of the bullet + Block system
Now let's use the moment to solve the shock
Before the crash
p₀ = m v₀
After the crash

The system is formed by the bullet and block assembly, so the forces during the crash are internal and the moment is preserved

m v₀ = (m + M) v
v₀ = v (m + M) / m
let's calculate
v₀ = 27.83 (0.012 +0.109) /0.012
v₀ = 280.6 m / s
Distance is the total length covered = 2m + 3m = 5m
Displacement is his distance from original position.
Displacement = 2m + (-3)m. Representing the 3m walked back as -3.
Displacement = 2m - 3m = -1m.
So his displacement is 1m behind his original starting point.