Thread: [SOLVED] can someone explain how she found the phase shift

a certain mass is supported by a spring so that it is at rest 0.50m above a table top. The mass is pulled down 0.40m and releasted at time t=0sec, the highest position of the mass is 0.90m. It takes 1.20s for the mass to return to the low position each time. Graph the function and find its height at 0.70s.


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i understand everything on the note except where she determined the shift...


from the question i know that the initial height is at 0.50m at 0s ... and the max height is 0.90 at 0.6s ...

can someone just explain it a little more

Originally Posted by rock candy

a certain mass is supported by a spring so that it is at rest 0.50m above a table top. The mass is pulled down 0.40m and releasted at time t=0sec, the highest position of the mass is 0.90m. It takes 1.20s for the mass to return to the low position each time. Graph the function and find its height at 0.70s.


ImageShack - Image Hosting :: 98929921.jpg


i understand everything on the note except where she determined the shift...


from the question i know that the initial height is at 0.50m at 0s ... and the max height is 0.90 at 0.6s ...

can someone just explain it a little more

By shift I think you are talking about the shift in the graph

-See the graph is between "t" in x-axis and "y" in y-axis

-First of all she determined the equation when all initial values are zero

-So In the initial condition t and y have value (0,0)

- In the second case as you have written the values have changed accordingly
as the "real function"

-So in order to represent the real function the values of t and y need to be displaced

-Now how much should the displacement be so that our dummy equation becomes the "real" one

- See her calculation

-General Rule :Now when a function in x and y is shifted to (a,b) then inorder to shift the complete graph replace every x by (x-a) and y by (y-b)

-that's what she has done with t and y

Ask incase you still find it difficult