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#1 2011-03-18 14:15:05

Au101
Member
Registered: 2010-12-01
Posts: 353

Dynamics

Hi guys, I have a mechanics question on what I think is dynamics.

A particle P of mass 2 kg is acted on by two forces

And

(a) Show that the acceleration of P is

Which we do with

At time t = 0 P is at the point with position vector

Relative to a fixed origin O and has velocity

Calculate at time t = 3 seconds

(b) The velocity of P

Which is:

(c) The position vector of P

Here is where I am stuck. Does anybody have any suggestions? Thanks.

Last edited by Au101 (2011-03-18 14:22:27)

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#2 2011-03-21 21:36:25

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

Re: Dynamics

Fnet=(6i+2j)
anet={Fnet/2}=(3i+j)........Ans
Vx=V(initial)+ax*t
     4+3*3=13
Vy=0+3*1=3
Vnet=Vxi+Vyj
      (13i+3j).........Ans
X=X0+v(initial)*t+1/2*ax*t^2
  =2+4*3+1/2*3*9
  =27.5
Y=Y0+0+1/2*1*9
=-1+4.5
=3.5
="hence requried position vector=(27.5i+3.5j)".........Ans

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#3 2011-03-22 04:19:41

Au101
Member
Registered: 2010-12-01
Posts: 353

Re: Dynamics

Aha, got it. Thanks Sameer smile

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