Originally Posted by

**GrahamJamesK** Suppose a particle of mass 1 kg is initially at (1, 0, 0) and with initial

velocity ˆ−j +2ˆk and moves under a constant force F = −i +2ˆj. Find

the position and velocity for all time.

The Equation of motion ma = F implies that,

a = −i +2ˆj

which gives the three scalar equations:

d^2x/dt^2= −1,

d^2y/dt^2= 2,

d^2z/dt^2= 0

integrating for x yields:

x = −1/2t^2+1

integrating for y yields:

y = t^2− t

I am unable find z, where:

d^2z/dt^2 = 0

I need to integrate this equation twice to obtain:

z = 2t

But as far as i understand integrating 0 yields 0. I have a feeling that I'm overlooking something simple but at present it is escaping me and i cannot figure out how to arrive at the given value.

Any help or advice would be greatly appreciated as I am finding this area of Applied math confusing.