Find gravity on an unknown planet

[dragon18]

Starting from rest, an object is sliding down a frictionless inclined plane on the planet Org. Using the animation, determine the acceleration due to gravity ('g') on the planet. Use the protractor shown on the screen to measure the angle of inclination.
https://www.physicsforums.com/attachments/55979
point 1: 0s 0,30
point 2: 1s 2.6, 27.2
point 3: 2s 10, 21.7
point 4: 3s 22.7, 12.6
point 5: 4s 40, 0
Theta: 36.15

Relevant Equations
a=v_f-v_f
a=gsinθ



Attempt
v_i=0m/s
v_f=7.5m/s
a=7.5m/s²

g=sin36.15/7.5
g=0.0787m/s²

 

[Simon Bridge]

Please show your working and the reasoning behind it.

Note:
Invalid Attachment specified.
You have a mistake in one of your equations.

if a=7.5m/s² and v_i=0 as you have stated,
then
1. what is the speed after 1 second?
2. does this agree with the data?