Shm Help!!!! (1 Viewer)

[star*eyed]

How do I find the amplitude of motion??

If i know the two end points is it just those divided by two??
cause im doing the 1993 past paper and the question reads

the velocity v of a particle moving in shm along the x axis is given by
v^2 = 8 + 2x - x^2

Between which two points in the particle oscillating?
i got the answer to this
-2 and 4

but the next question is
What is the amplitude of motion?

and in the answers it just says 4-(-2) / 2 <------ why is this? wat formula?
=3

 

[acmilan]

Subtract the endpoints and divide by 2

Normally you'd do larger endpoint - smaller endpoint, if you do it the other way you'll get a negative amplitude, which just needs to be made positive.

 

[Riviet]

You can also find the centre of motion and subtracting that from either of the endpoints, then taking the absolute value since the amplitude is a distance.

-2 | -1 | 0 | 1 | 2 | 3| 4 |

So centre of motion is at x=1, subtract 1 from 4 and you get 3. Subtract 1 from -2 to get -3 and take the absolute value to get 3.