Answer: B
Longitudinal wave
Explanation:
Transverse waves have crests and troughs
Longitudinal waves have compressions and rarefactions. A compression is where the density of the wave medium is highest. While a rarefaction is where the density of the wave medium is lowest.
Since sound wave is a longitudinal wave. And longitudinal wave exists apart from sound, we can therefore conclude that it's a longitudinal wave in spring.
A) law of inertia. an object in motion stays in motion
Answer:
The self-induced emf in this inductor is 4.68 mV.
Explanation:
The emf in the inductor is given by:

Where:
dI/dt: is the decreasing current's rate change = -18.0 mA/s (the minus sign is because the current is decreasing)
L: is the inductance = 0.260 H
So, the emf is:

Therefore, the self-induced emf in this inductor is 4.68 mV.
I hope it helps you!
Luster I think is what you are looking for
A=F/m
a=(3000000)/(20000)
a=15 m/s^2