  A scalar has only magnitude. A vector has magnitude and direction.   Acceleration is a vector because it has magnitude and direction. That's why an o â¦ bject can be said to be accelerating if it has a circular rotation and a constant speed; even though it's speed isn't changing, it's direction constantly is. vector has magnitude and direction.   Acceleration is a vector because it has magnitude and direction. That's why an o â¦ bject can be said to be accelerating if it has a circular rotation and a constant speed; even though it's speed isn't changing, it's direction constantly is.
Chronic dry coughs are usually caused by irritation from cigarette smoke, environmental irritants, allergies, postnasal drip, or asthma. Several chronic lung diseases also cause a dry, hacking cough. Some people cough out of habit for no clear reason. Gastric reflux may also cause a chronic dry cough. Usually you will also have other symptoms, such as heartburn, burning in the throat, or increased saliva.
THROAT-Â­CLEARING COUGH. It feels like you have a lump in your throat and coughing leaves you with a nasty, bitter taste in the mouth. The cough can be Â­triggered by talking, laughing, singing or eating particularly dry food. It also tends to occur at night. CAUSE: The most likely cause is stomach acid splashing up the Â­gullet â this affects about 25 per cent of the adult Western Â­population and is known as reflux.