Acar traveling at 12 m/s slows down at a constant rate
for 4 seconds until it stops. what is its acceleration?

The deceleration of the car is 3 m/s².

Explanation:

So the initial velocity of the car is given as 12 m/s. As the car is said to slow down and then it stops after 4 seconds, so the final velocity is zero.

We know that the acceleration acting on any object to stop the motion of that object is termed as deceleration or negative acceleration.

This is because, acceleration is the ratio of change in velocity to time taken for that change in velocity.

So.,

So the deceleration of the car is 3 m/s².

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia