Math Is Fun Forum

IBmath_sl

Member

Registered: 2008-02-07

Posts: 1

Need help with vectors..Much APPRECIATION!

The topic is called Lines in the Plane and in Space...

1. Submarine A is at (2,4) and fires a torpedo with velocity vector [ 1 ,-3] (i can't do it vertically so i hope you can understand the vectors) at exactly 2.17 pm.
Sunmarine B is at (11, 3) and has velocity vector (-1, a). It fires a torpedo 2 minutes later to intercept the torpedo from A. Given that the interception occurs:
a Find x(t) and y(t) for submarine A
b Find x(t) and y(t) for   "     "      B
c At what time does the interception occur?
d What was the direction and speed of the interception torpedo?

2. Trapezium (trapezoid) KLMN is formed by these lines:
Line 1 (KL) is [x, y] = [2, 19] + p[5, -2]
Line 2 (ML) is [x, y] = [33, -5] + q[-11, 16]
Line 3 (NK) is [x, y] = [3, 7] +r[4, 10]
Line 4 (MN) is [x, y] = [43, -9] + s[-5, 2]
where p, q, r and s are scalars. Lines 1 and 2 meet at L(22,11). Lines 1 and 3 meet at K, Lines 2 and 4 meet at M, lines 3 and 4 at N.

a. Which two lines are parallel? Why?
b. Which lines are perpendicular? Why
c. use vector methods to find the coordinates of K, M and N.
d. Calculate the area of trapezium KLMN.

3. For A(3, -1, 1) and B(0, 2, -1), find the:
a Vector equation of the line passing through A and B
b The coordinates of P which divides BA in the ratio 2:5

4. Find the coordinates of the foot of the perpendicular from Q(-1, 2, 3) to the line x = 2 - t, y = 3 + t, z = -2t.

That's it...really thanks if you do it for me !!

jlo~

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Need help with vectors..Much APPRECIATION!

#1 questions.
  Is sunmarine B moving? or is the -1,a the torpedo?
  a.) do you want x&y(t) for the A's torpedo or sub?
  b.) torpedo or sub movement equation?
  c.) units of time will be called just generic timeunits?
  d.) Does the motion of the sub affect the motion of
      the missile only in the component of the sub's motion
      that is in-line or along the path of the missile??  Since
      missiles are long, they won't go side-ways in water.

---

igloo myrtilles fourmis

IBmath_sl

Member

Registered: 2008-02-07

Posts: 1

Re: Need help with vectors..Much APPRECIATION!

Jee, someone's hilarious