Basic motion stuffs, time and velociton

[k3l]

Basic motion stuffs, time and velociton :(

hi
oh my gosh... i can't believe i forgotten how to do this...
i have to work out the time when will the two particles meet... where one particle (A) is traveling at a velocity of 80km/h, and (B) is traveling with a velocity of 100km/h while (B) is 350km behind (A)
(assume they are traveling toward the same directions)

thx

 

[snow]

s_a = s_b
s_a = s_0 + v_a * t
s_b = v_b * t

Insert both in first equation and calculate t.

 

[moose]

Basic algebra.

Distance=rate x time

D1=x
D2=x+350
so for the equation distance = rate x time just plug in x and x+350 as your distance, use t for time
since x is the same value, you can combine the two and solve for t.

 

[DB]

I'm a bit confused, do you add the 2 distances?
x+x+350=100 \\ or \\ 80? *t?
Maybe I'm stupid but I'm confused...

 

[Nenad]

use relative time frames. Take the moving particles frame that is behind the other particle, subtract the other cars speed and no consider that the other particle is stationary.

V_{slower\ particle} = 80km/h
V_{faster\ particle} = 100km/h
V_{faster\ particle\ relative\ to\ slower\ one} = 100km/h - 80km/h = 20km/h

now your system becomes linear.

use:

d = Vt

you should know what to sub in where.

Regards,

Nenad