# Acceleration, Displacement, Graph Interpretation

• lthcn99
In summary, the conversation discusses the concept of acceleration and its relationship to velocity in a graph. The individual is asked to find the acceleration rate for specific time periods and also to use it to calculate the normal force and displacement. They also question the possibility of negative acceleration and its examples in real life scenarios. The conversation ends with a question about finding the tension of an elevator with a weight of 500 kg.
lthcn99
Hello, I was working on a worksheet. It gave a graph that was velocity vs. time. I was asked to find the acceleration rate for the given (specific) time in seconds. My first question is if the line on the graph for example is from 1-3 seconds, in that 1-3 second range, is acceleration constant? And is it possible to have a negative acceleration? After finding the acceleration, I was asked to find the Normal Force using those acceleration and a person who weights 65 kg. Do I just use F=ma? Then I was asked to find I guess the displacement from 0-8 seconds. Do I make triangles, find area, and add them all up? Then lastly it asked if a elevator was 500 kg, what would be the tension pulling it. I'm hoping someone can help. Thank you.

lthcn99 said:
Hello, I was working on a worksheet. It gave a graph that was velocity vs. time. I was asked to find the acceleration rate for the given (specific) time in seconds. My first question is if the line on the graph for example is from 1-3 seconds, in that 1-3 second range, is acceleration constant? And is it possible to have a negative acceleration? After finding the acceleration, I was asked to find the Normal Force using those acceleration and a person who weights 65 kg. Do I just use F=ma? Then I was asked to find I guess the displacement from 0-8 seconds. Do I make triangles, find area, and add them all up? Then lastly it asked if a elevator was 500 kg, what would be the tension pulling it. I'm hoping someone can help. Thank you.
View attachment 212471

PF rules require that YOU do some work first (and show what you have done) before asking for help here.

It ask me what would be the acceleration rate for 1 seconds. So I did A=vf-vi/t and got 4 m/s2 because y=8 and x=2 secs. But then it asks for the acceleration rate for 1.5 seconds, so will it still be 4 m/s2 cause it is constant? Then it ask for the acceleration rate for 6.5 seconds. I wasn't sure what to do so I did -8/6 and got -1.33 m/s2.
Part B ask what would be the normal force with a person of 65 kg. I'm confuse whether to use f=ma or N=f-mg. Like am I using the acceleration from above to solve this? I used f=ma, 65 x 4 = 260 N. 65 x -1.33 = -86.45 N.
For finding displacement, I went to find the areas of triangles from the graph. From 0-2 seconds is one triangle, so 1/2(b)(h), 1/2(2)(8)=8m. Then 3-4 seconds, I got 4 m. So I'm assuming from 0-4 secs, the displacement is 12m.

Do you know what acceleration represents? What happens to velocity during time periods when acceleration is zero? What would the velocity graph look like during those time periods? You asked if negative acceleration is possible. The answer is yes. Try to think of examples of when acceleration is negative. Think about when you are driving or riding in a car. What horizontal accelerations act on you. When are the positive? When negative? When is acceleration zero?

lthcn99 said:
Then lastly it asked if a elevator was 500 kg, what would be the tension pulling it.

Hint: Tension is a Force. Find out what is 500kg and how would it be related in finding the tension pulling it upwards.

## What is acceleration?

Acceleration is the rate of change of velocity over time. It is a vector quantity, meaning it has both magnitude and direction. It is typically measured in meters per second squared (m/s²).

## How is acceleration calculated?

Acceleration can be calculated by dividing the change in velocity by the change in time. This can be expressed as the formula a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

## What is displacement?

Displacement is the change in position of an object from its initial position to its final position. It is a vector quantity and is typically measured in meters (m).

## How is displacement represented on a graph?

Displacement is usually represented on a graph as the vertical position of an object over time. The slope of the displacement vs. time graph represents the velocity of the object, and the area under the curve represents the total displacement of the object.

## What can we learn from interpreting a graph of acceleration vs. time?

A graph of acceleration vs. time can tell us how an object's acceleration changes over time. A constant positive slope indicates a constant acceleration, while a flat line indicates zero acceleration. A negative slope indicates a decreasing acceleration, and a downward curve indicates a decreasing velocity and negative acceleration. The area under the curve represents the change in velocity of the object.

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