# Acceleration of an elevator

1. Nov 18, 2007

### Prathep

I need help getting started with this problem. Thanks.

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

The acceleration of an elevator changes at a rate give by the function

Plot the position of the elevator assuming that its velocity at t=0 is zero and the elevator starts moving from a zero ground level.

2. Relevant equations

3. The attempt at a solution

2. Nov 18, 2007

### dynamicsolo

Are you in a calculus-based physics course? The problem sounds like it calls on you to integrate this acceleration function to find the velocity function, then to integrate that to find a positive function, given that v(0) = 0 and x(0) = 0.

This will be harder to deal with if you have to do it only graphically.

3. Nov 18, 2007

### Prathep

I could use integration to solve this, then I have to use the values to plot a graph.
Still need help staring this problem. Thanks.

4. Nov 18, 2007

### dynamicsolo

So wouldn't you be plotting the values of x(t) for different times? Also, is e in that function supposed to be 2.71828... ? So you have all the information you need to find the position function and calculate positions, no?

5. Nov 22, 2007

### Prathep

e = 2.71828183

I have integrated the acceleration equation twice to find out position. Then I plotted the equation on Maple and i got this graph, Can someone tell weather this is correct or incorrect way of addressing this problem. I also can't understand the Graph, according to the graph it says the the position of the elevator increases exponential after 5 second. Can someone explain the graph to me. Thanks

Last edited: Nov 22, 2007
6. Nov 22, 2007

### Hells_Kitchen

- First of all it does not make sense to plot the position time graph for negative time values. You should graph the position function for t>=0

- Secondly as for explaining the graph for positive t values note the following:
The elevator at t = 0 starts at about 14 units away from the origin of your frame of reference and for t = 4 it will come towards the origin and then for t>4 it will move away from the origin.

7. Nov 22, 2007