# Acceleration, Displacement, Graph Interpretation

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. Related Introductory Physics Homework Help News on Phys.org
Ray Vickson
Homework Helper
Dearly Missed
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.
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lthcn99
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.

scottdave