A brake warning lamp on the dash remains on whenever the ignition is on. If the wire to the pressure differential switch (usually a part of a combination valve or built into the master cylinder) is unplugged, the dash lamp goes out. Technician A says that this is an indication of a hydraulic brake problem. Technician B says that the problem is probably due to a stuck parking brake cable switch. Which technician is correct?

The answer is Technician A only is correct.

Explanation:

From the statement that a brake warning lamp on the dash remains usually on whenever the ignition is on, thus if the wire to the pressure differential switch (usually a part of a combination valve or built into the master cylinder) is unplugged, the dash lamp goes out. This is an indication of a hydraulic brake problem because the wire to the brake switch is disconnected thus causing no reportage. Normally, the brake warning lamp supposed to be on  usually except if faulty or wire is disconnected as described above.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.