# Force Diagram, Position vs Time Plot: Construct, Calculate, Sketch

• BrownBoi7
In summary, the conversation discusses the construction of a Velocity vs Time plot for an elevator and the calculation of average acceleration and Normal force for a given time interval. The plot and calculations are necessary for understanding the motion of an occupant within the elevator.
BrownBoi7
The vertical motion of an elevator is recorded and a Position vs Time plot is generated. The plot is shown in the image attached.

1. Construct a scale drawing of the associated Velocity vs Time plot complete with axis labels.

2. Calculate the average acceleration for the time interval t =8.0s to t = 10s.

3. Sketch a force diagram of an elevator occupant with a mass of 70 kg during the time interval t =8.0s to t = 10s.

4. Calculate the Normal force F N of the occupant using the acceleration you calculated in part 2

Can somebody please tell me where I went wrong? Thanks!

Mt attempt:
1. Velocity during 0 to 10 = 14 m / 10 s = 1.4 m/s
Velocity during 10 to 19 = 0 m/s
Velocity during 19 to 25 = -14 m /6 s = - 2.33 m/s

2. a = delta v/delta t = 0 - 1.4 m/s/2 s = -0.7 m/s^2

3. I have no clue. How do you figure this one out?

4. Fn = 70 kg * -2.33 m/s^2 = -163.10 N

#### Attachments

• p vs t graph.JPG
15.9 KB · Views: 472
3. you know the mass and the acceleration, so you know the force for the asked interval.

Yea but apparently my answers to other questions are also wrong. I don't know what's the problem. And 3 is asking for a force sketch.

## 1. What is a force diagram?

A force diagram is a visual representation of the forces acting on an object. It uses arrows to show the direction and magnitude of each force.

## 2. How do I construct a force diagram?

To construct a force diagram, you must first identify all the forces acting on the object. Then, draw a dot or a box to represent the object and draw arrows to represent each force, making sure to label them with their corresponding magnitude and direction.

## 3. What is a position vs time plot?

A position vs time plot is a graph that shows an object's position at different points in time. The position is plotted on the y-axis and time is plotted on the x-axis.

## 4. How do I calculate an object's position from a position vs time plot?

To calculate an object's position from a position vs time plot, you can use the slope of the line on the graph. The slope represents the object's velocity, and the position can be calculated by multiplying the velocity by the time.

## 5. How do I sketch a position vs time plot?

To sketch a position vs time plot, you must first determine the object's position at different points in time. Then, plot these points on the graph and connect them with a line. Make sure to label the axes and include a legend if necessary.

Replies
17
Views
1K
Replies
9
Views
521
Replies
1
Views
2K
Replies
1
Views
8K
Replies
5
Views
3K
Replies
5
Views
2K
Replies
3
Views
10K
Replies
38
Views
3K
Replies
6
Views
2K
Replies
33
Views
7K