Vector confusion.

• May 5th 2008, 02:00 PM
Mr. Edward
Vector confusion.
how can I explain in my own words the difference of a scalar and a vector?

How do I draw a vector to represent the folllowing
a) The velocity of a fishing boat travelling at 8 knots on a heading of S75^oW
d) The force exerted by a chain hoist carrying a load of 200kg.

This is the most confusing for me. The points A, B, C, D, E, F, G are equally spaced along a line. Name a vector which is equal to 3(BD)Vector arrow symbol on top BD.
b) 1/4EA(Again Arrow symbol)
• May 5th 2008, 03:08 PM
Reckoner
Quote:

Originally Posted by Mr. Edward
how can I explain in my own words the difference of a scalar and a vector?

If I told you, would it really be your own words? (Happy)

A vector indicates both a magnitude and a direction. What can you represent with a scalar?

Quote:

Originally Posted by Mr. Edward
How do I draw a vector to represent the folllowing
a) The velocity of a fishing boat travelling at 8 knots on a heading of S75^oW
d) The force exerted by a chain hoist carrying a load of 200kg.

Again, a vector gives a magnitude and a direction. For a, our magnitude is 8, and our direction is $75^\circ$ west of south. For b, the direction of the force should be opposite that of gravity.

Quote:

Originally Posted by Mr. Edward
This is the most confusing for me. The points A, B, C, D, E, F, G are equally spaced along a line. Name a vector which is equal to 3(BD)Vector arrow symbol on top BD.
b) 1/4EA(Again Arrow symbol)

Two vectors are equal if they have the same magnitude and the same direction. So, your goal for the first part is to find a vector with
the same magnitude and direction as $3\overrightarrow{BD}$. Now, what section of the line is three times the length of $\overrightarrow{BD}$? From $A$ to $C$ is $1\overrightarrow{BD}$, from $C$ to $E$ is $2\overrightarrow{BD}$, and from $E$ to $G$ is $3\overrightarrow{BD}$, correct? And any vector drawn between two points on that line should run parallel to $\overrightarrow{BD}$, so you should have equal magnitude and equal direction. Do you see?

Solve part b the same way.