Scalars an d vectors

Question 1

scalar definition

Answer 1

physical quantities that have a numerical magnitude only. eg. time, mass

1kg + 1kg = 2kg

Question 2

vector

Answer 2

physical quantities that have both numerical magnitude and direction. eg, force, acceleration

if 1.0N and 1.0N both go to the left then the total force going to the left is 2.0N

if 1.0N goes left and 1.0N goes right then total force is 0.0N

so direction matters here

Question 3

how to represent direction in vectors

Answer 3

by changing the sign.
if +100N is going to the left, to represent 100N going to the right we write -100N

Question 4

whats a resultant vector

Answer 4

A resultant vector is the vector sum of two or more vectors. It’s the resulting vector that combines the effects of all the individual vectors.

Question 5

what is (TTT)

Answer 5

tip-to-toe method (TTT)
this is a graphical method and uses trigonometric calculations to find a resultant vector

Question 6

how to use (TTT) to find a resultant vector

Answer 6

1.) identify a scale -> 1cm : 3 N
2.) drawing an arrow to represent the 1st vector to its scale and direction.
3.) drawing the start of subsequent vectors from the end of the preceding vector

4.] the resultant vector is the line connecting the start of the first vector to the end of the second vector. (added vector)
4.] if the end of the last vector is the beginning of the first vector.. then the resultant is a zero or null vector (never ending triangle)

Question 7

how to state the direction of a force

Answer 7

state the angle it is from a known force then the direction
e.g. 50deg anti-clockwise of 25N, or 37deg clockwise of north

Question 8

what is pythagoras theorem

Answer 8

a^2 + b^2 = c^2

Question 9

how to find resultant vector using splitting method

Answer 9

1. theres 2 vectors, pointing in random directions like upwards diagonally left.
2. split these 2 vectors into 4 vectors.
3. these 4 vectors should only have the cardinal directions
4. add up these forces. if opposite forces then they cancel each other
5. this will lead to 2 vectors of a cardinal direction.
6. use pythagoras to get the hypotnuse which is the resultant vector

Question 10

what is a bearing

Answer 10

the angle clockwise from north

Question 11

what is cosine rule

Answer 11

c² = a² + b² - 2ab * cos(C)
small caps is side name
big caps is angle

Question 12

what is sine rule

Answer 12

a / sin(A) = b / sin(B) = c / sin(C)
small caps is side name
big caps is angle