Qualification > Math
All Mechanics DOUBTS HERE!!!
Phosu:
A particle P is moving with constant velocity (–5i + 8j) m s–1. Find
(a) the speed of P,
(b) the direction of motion of P, giving your answer as a bearing.
At time t = 0, P is at the point A with position vector (7i – 10j) m relative to a fixed origin O. When t = 3 s, the velocity of P changes and it moves with velocity (ui + vj) m s–1, where u and v are constants. After a further 4 s, it passes through O and continues to move with velocity (ui + vj) m s–1.
(c) Find the values of u and v.
(d) Find the total time taken for P to move from A to a position which is due south of A.
plz tell me how to solve part d
halosh92:
--- Quote from: Phosu on May 06, 2010, 02:25:30 pm ---A particle P is moving with constant velocity (–5i + 8j) m s–1. Find
(a) the speed of P,
(b) the direction of motion of P, giving your answer as a bearing.
At time t = 0, P is at the point A with position vector (7i – 10j) m relative to a fixed origin O. When t = 3 s, the velocity of P changes and it moves with velocity (ui + vj) m s–1, where u and v are constants. After a further 4 s, it passes through O and continues to move with velocity (ui + vj) m s–1.
(c) Find the values of u and v.
(d) Find the total time taken for P to move from A to a position which is due south of A.
plz tell me how to solve part d
--- End quote ---
how did u do part (c) first of all?
Phosu:
first find the new vector position using the initial velocity, for first 3 sec
(7i-10j) +(-5+8j)3 = -8i+14j
after the boat reaches this vector position it changes speed, and travels for 4s until it reaches origin O which is O so
0=(-8i+14j)+(ui+vj)4
0=(-8+4u)i+(14+4v)j
now solve seperately
-8+4u=0 u=2
14+4v=0 v=-3.5
new velocity (2i-3.5j)
halosh92:
--- Quote from: halosh92 on May 06, 2010, 01:39:40 pm ---at 2.p.m. the position vector relative to a lighthouse of ship A is (3i+j)km and its velocity is (-i + 5j)km/h
At the same time ship B has position vector (-i + 4j)km relative to the lighthouse and velocity (2i + 3j)km/h . find, after "t"h
a) the position vector of A relative to the lighthouse.
b)the position vector of B relative to the lighthouse.
c)the position vector of A relative to B.
d) find the time when A is due north of B.
can someone just solve part (d) how to come about such questions wat do they mean exactly?
--- End quote ---
could someone plzz solve this ?
:-[ :-\
T.Q:
--- Quote from: halosh92 on May 08, 2010, 09:15:08 pm ---could someone plzz solve this ?
:-[ :-\
--- End quote ---
(i) component of A will be equal to the (i) component of B
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version