# Homework Help: Understanding particular movement

1. May 3, 2010

### Susanne217

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

If the time of a particles movement at a certain position can be described

$$t_k = t_{k-1} + \Delta t$$

write an expression for the velocity at $$t_k$$

2. The attempt at a solution

if I assume that the corresponding position of the particle is

$$s_k = s_{k-1} + \Delta s$$

then it follows

that $$\frac{s_k}{t_k} = \frac{t_{k-1} + \Delta t}{s_{k-1} + \Delta s} = \frac{t_{k-1}}{s_{k-1}} + \frac{\Delta s}{\Delta t}$$

where $$\frac{s_{k}-s_{k-1}}{t_{k}-t_{k-1}} = \frac{\Delta s}{\Delta t} = v(t_i)$$

Can I assume this? No information about s is given. I am just using theory from my textbook..

Last edited: May 3, 2010