Question

What does it mean if you were asked to " discuss the validity of extrapolating the acceleration value to angle of 90 degrees"?

Answer 1

It means how well are the extrapolated values of g compare with the accepted value of free fall acceleration which is 9.81 m/sec2.

when the angle is 90 degrees, the value of g will be below the accepted values to an error of nearly 1.33 %

It is valid to extrapolate the acceleration value to an angle of 90 degrees because there is a mathematical relationship between the angles of incline and the acceleration of an object rolling down the frictionless incline. The acceleration of the object is always a function of the sine of the incline angle times the perpendicular acceleration. This value can be found by finding g at different angles. The resulting data will show a trend which can be used to extrapolate the acceleration g at different angles.