Which Homework Questions Deal with Vector Quantities and Their Properties?

[ian_durrant]

I'm working on some homework and I've become stummped on two questions (one of them is wrong, the other is right). The bolded answer is the answer I've chosen.

Homework Statement

Question 3 10 points Save
Which one of the following quantities is a vector quantity?



A. the age of the earth


B. the mass of a freight train


C. the Earth's pull on your body


D. the temperature of hot cup of coffee


E. the number of people attending a soccer game


Question 4
Two vectors A and B are added together to form a vector C. The relationship between the magnitudes of the vectors is given by A + B = C. Which one of the following statements concerning these vectors is true?



A. A and B must be displacements.


B. A and B must have equal lengths.


C. A and B must point in opposite directions.


D. A and B must point in the same direction.


E. A and B must be at right angles to each other.


Anyone have any thoughts?

thanks for any help

 

[plutoisacomet]

Hello and welcome. Your questions will not be answered directly due to the rules of the forum. I see both questions are vector questions.

For question 3, look at each selection and see if you can assign it a Magnitude and a Direction. If so, you have a Vector. If not, you have a scalar.

For Questiion 4 Just apply your difinition of a vector and the qualities of a vector and you will easily answer the question yourself.
Good luck

 

[Moetasim]

It looks like you have chosen the correct answer for question 3 - C. The Earth's pull on your body is a vector quantity because it has both magnitude (strength) and direction.

For question 4, the correct answer is D. A and B must point in the same direction. This is because when two vectors are added together, the resultant vector (C) will have a magnitude and direction that is the sum of the two original vectors. Therefore, for A + B = C to be true, A and B must have the same direction. They do not necessarily have to be displacements or have equal lengths, and they do not have to be at right angles to each other.