  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.
There are many causes of a productive cough, such as: 1  Viral illnesses. 2  It is normal to have a productive cough when you have a common cold. 3  Coughing is often triggered by mucus that drains down the back of the throat. 4  Infections. 5  An infection of the lungs or upper airway passages can cause a cough.here are many causes of a nonproductive cough, such as: 1  Viral illnesses. 2  Bronchospasm. 3  Allergies. 4  Medicines called ACE inhibitors that are used to control high blood pressure. 5  Exposure to dust, fumes, and chemicals in the work environment. 6  Asthma. 7  Blockage of the airway by an inhaled object, such as food or a pill.