motion (1 Viewer)

[zazzy1234]

ok now im really pissed:mad1:, this topic is what i reallly HATE with a passion.


the accaleration of the particle of an object is given by a=1/x cm/s^2 and the particle is at rest when it is 3cm to the right of the origin. If the particle is always moving to the right, find the velocity of the particle when its displacement is 10cm (2dp)


answer: 1.55cm/s

thanx

 

[zazzy1234]

have to go but quickly:

write acceleration as v*(dv/dx)

v*(dv/dx) = 1/x

v dv = (1/x) dx

integrate both sides:
v^2/2 + C = ln(x)

sub in when: v=0, x=3 to get C

then just x = 10 and rearrange for v!

i got the wrong ans twice

 

[Aerath]

It gives the right answer. I just did it. the value of C above should be ln3.

 

[zazzy1234]

It gives the right answer. I just did it. the value of C above should be ln3.

yh i got the value of c right but ans wrong

 

[zazzy1234]

yh i got the value of c right but ans wrong

stupid meee. yehyeh it's right thanx sooooooooooo much.

 

[Aerath]

So, once you get c = ln3, rearrange, v^2 = 2ln(x/3)

Sub in x = 10

v^2 = 2ln(10/3)

square root.

v = 1.55

 

[zazzy1234]

So, once you get c = ln3, rearrange, v^2 = 2ln(x/3)

Sub in x = 10

v^2 = 2ln(10/3)

square root.

v = 1.55

yeh thanx i eventually got it, lol, um did ur read ur PM

 

[Drongoski]

 

[zazzy1234]

faaaaaaaaaaaaaaaaaaaaanxxxxxxxxxxx uz r really alot of help