Amass undergoes SHM with an amplitude of 5.7 cm. The energy is 16 J at this time. The mass is cut in
half, and the system is again set in motion with amplitude 5.7 cm. What is the energy of the system now?

16 J

Explanation:

A system in Simple Harmonic Motion  (SHM) is a system oscillating periodically around an equilibrium position, and having a restoring force proportional to the displacement that brings the system back towards the equilibrium position:

where

k is the spring constant of the system

x is the displacement wrt the equilibrium position

In a SHM, the total energy of the system is given by the equation

where

k is the spring constant of the system

A is the amplitude of motion (the maximum displacement)

In this problem, the initial energy of the system is

E = 16 J

when the amplitude is A = 5.7 cm.

Later, the mass is cut in a half, while the amplitude remains the same: A = A' = 5.7 cm.

However, we see that the energy in a SHM does not depend on the mass: therefore, since the amplitude has remained constant, the energy will remain the same.

a sonic boom is a loud boom that breaks the sound barrier

explanation:

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.