# A point with velocity, V

1. Mar 29, 2009

### Jack3145

1. The problem statement, all variables and given/known data

A point: $$[x_{0}, y_{0}, z_{0}, t_{0}]$$
It's velocity: $$V_{a} = [v_{1}, v_{2}, v_{3}, v_{4}]$$

What is wrong with this equation:

$$x^{b} = [x_{0} + v_{1} * t, y_{0} + v_{2} * t, z_{0} + v_{3} * t, t_{0} + t]$$

2. Mar 30, 2009

### CompuChip

Nothing is wrong with that, as long as V is a constant vector.
For example, if Va = (2, 3, 4, 1) then your formula for x satisfies v = dx/dt.
However, if Va = (3t, t2, 3t - 12, t2/6) it doesn't.