# Pure maths vector help

Watch
Announcements

Page 1 of 1

Go to first unread

Skip to page:

Report

#2

(Original post by

can someone help me figure out these questions

**soph1a**)can someone help me figure out these questions

1) this is the Cars and Motoring section

2) you haven't posted any questions

Moved to the Maths section, but it'd probably help if you did post the questions!

2

reply

Report

#5

(Original post by

can someone help me figure out these questions

**soph1a**)can someone help me figure out these questions

0

reply

Okay hopefully this is the last time I make this thread Im just going to copy and paste the questions over

0

reply

(Original post by

we will try & help on the Maths forum. please post the questions.

**the bear**)we will try & help on the Maths forum. please post the questions.

- Forces F1 and F2 act on a particle

F1 = -3i + 7j newtons

F2 = i-j Newtons

Resultant force R acting on the particle is given by R=F1+f2

a. Calculate magnitude of R in newtons (I get this bit)

b. Calculate the angle between the line of action of R and the vector j (donβt get this bit)

Iβm self teaching myself maths from the book so Iβm struggling with more problem based questions

__Question 2:__

- For each of the following vectors, find

i. a unit vector in the same direction

ii. the angle the vector makes with i

c= -9i+40j (this is the vector)

__Question 3:__

Small boat S, drifting in the sea, is modelled as a particle moving in a straight line at constant speed. When first sighted at 09:00, S is at a point with position vector (-2i-4j(km relative to a fixed origin O, where i and j are unit vectors due east and due north respectively. At 9:40, S is at the point with position vector (4i-6j)km.

a. Calculate the bearing on which S is drifting

b. Find the speed of S

PS: Im getting a maths tutor after Iβve finished teaching myself Pure Maths 1 so Iβm not looking for the answers to these questions, Iβm looking for how to go about solving them. Thank you

0

reply

Report

#8

(Original post by

[ul]

[li]Forces F1 and F2 act on a particle[/li]

[/ul]

F1 = -3i + 7j newtons

F2 = i-j Newtons

Resultant force R acting on the particle is given by R=F1+f2

a. Calculate magnitude of R in newtons (I get this bit)

b. Calculate the angle between the line of action of R and the vector j (donβt get this bit)

**soph1a**)[ul]

[li]Forces F1 and F2 act on a particle[/li]

[/ul]

F1 = -3i + 7j newtons

F2 = i-j Newtons

Resultant force R acting on the particle is given by R=F1+f2

a. Calculate magnitude of R in newtons (I get this bit)

b. Calculate the angle between the line of action of R and the vector j (donβt get this bit)

**j**direction is North. they want the angle between

**R**and the North direction.

0

reply

Report

#9

Q2 to find a unit vector you divide the vector by its magnitude

for instance the vector 3

the angle between

for instance the vector 3

**i**- 4**j**has magnitude 5, so the unit vector would be .6**i**- .8**j**the angle between

**c**and the**i**direction is the angle between**c**and the East
0

reply

Report

#10

Q3 you need to find the vector connecting the original position to the new position:

for instance:

original = 12

new = 8

connecting vector = -4

the distance traveled = magnitude of the connecting vector = 5

if this takes 1 hour and 15 minutes....

speed = distance/time = 5/1.25 = 4 km/hr

for instance:

original = 12

**i**+ 3**j**new = 8

**i**+ 6**j**connecting vector = -4

**i**+ 3**j**the distance traveled = magnitude of the connecting vector = 5

if this takes 1 hour and 15 minutes....

speed = distance/time = 5/1.25 = 4 km/hr

0

reply

X

Page 1 of 1

Go to first unread

Skip to page:

### Quick Reply

Back

to top

to top