A scalar is just a number, and a vector is a number with a direction involved.
In the first question, pounds, newtons, and dynes are all *forces*. A force can’t exist as just a number; force has to be directed somewhere. 2 kilometers/hour east gives you a number and a direction. The answer a) is just a speed. You can know something is traveling 2 miles/hr without knowing what direction it’s traveling. You can’t say something is simply exerting 2 pounds of force; it has to be exerting it on something else.
In the second question, we’ve already said that 2 miles per hour was a scalar. 2 apples is obviously directionless. 2 kilograms and 2 liters just tell you how much of something you have. 2 ounces here must mean ounces in a pound rather than fluid ounces. So these are a weight, which is again a force and has to be directed somewhere.
Another example:-
I need to know what the difference is between them to answer these questions:
Which of the following is NOT a vector quantity?
a.) 2 miles per hour
b.) 2 pounds
c.) 2 newtons
d.) 2 kilometers per hour east
e.) 2 dynes
Which of the following is NOT a scalar quantity?
a.) 2 miles per hour
b.) 2 kilograms
c.) 2 apples
d.) 2 ounces
e.) 2 liters
I’m not looking for you to answer the questions as I already know the answers[ a.) and d.) – from the book] but I need to know the difference between a scalar and vector quantity so I can answer them myself. The book is simply a workbook and has no explanations.
