Chart not plotting data correctly (Visual Basic) - vb.net

Question

I am having problems with a project which should show the acceleration of a simple pendulum swinging over time. It should model a negative cosine curve, and I have the X and Y axis set so that the cosine curve will peak at the top of the chart area. However, it does not do this. For example, the maximum acceleration is calculated to be 17.746 m/s^2, however on the chart it says the maximum is around 1.71 m/s^2. Screenshot attached below.
https://drive.google.com/file/d/1AcmIDXsJIbzihH8Nq4mgSn1CofJCkQ6T/view?usp=sharing
I have wondered whether my maths are wrong or whether the problem lies somewhere in the chart. I have two other charts working, displacement and velocity of the pendulum, so I am confused as to why this will not work, especially as the coding behind each different chart is almost identical. I will attach all necessary code beneath.
Private Function CalculateAcceleration(ByVal amplitude As Double, ByVal frequency As Double, ByVal time As Double) As Double
Dim acceleration, maxAcc As Double
maxAcc = sq((2 * PI * frequency)) * amplitude
acceleration = -(maxAcc * Cos(2 * PI * frequency * time))
Return acceleration
End Function
Private Sub CreateAccelerationGraph(ByVal angularSpeed As Double, ByVal amplitude As Double, ByVal timePeriod As Double, ByVal frequency As Double)
If AccelerationChart.Series("Acceleration").Points.Count <> 0 Then
AccelerationChart.Series("Acceleration").Points.Clear()
End If
Dim maxAcceleration As Double = sq(angularSpeed) * amplitude
With AccelerationChart.ChartAreas("Default")
.AxisX.Minimum = 0
.AxisX.Maximum = (1 * timePeriod)
.AxisY.Minimum = -(maxAcceleration)
.AxisY.Maximum = maxAcceleration
End With
Dim increment As Double = (1 * timePeriod) / 100
For time As Double = 0 To (1 * timePeriod) Step increment
Dim xPos, yPos As Double
yPos = CalculateAcceleration(amplitude, frequency, time)
xPos = time
AccelerationChart.Series("Acceleration").Points.AddXY(xPos, yPos)
Dim label As New CalloutAnnotation
With label
AccelerationChart.Annotations.Add(label)
End With
Next
End Sub
Private Sub SetUpAccelerationGraph()
Dim innerPlotPosition As ElementPosition = New ElementPosition(10, 10, 80, 80)
AccelerationChart.Series.Add("Acceleration")
AccelerationChart.ChartAreas.Add("Default")
With AccelerationChart.Series("Acceleration")
.Color = Color.BlueViolet
.BorderWidth() = 5
.ChartType = DataVisualization.Charting.SeriesChartType.Spline
End With
With AccelerationChart.ChartAreas("Default")
.IsSameFontSizeForAllAxes = True
.InnerPlotPosition = innerPlotPosition ' sets the inner plot position
End With
AccelerationChart.ChartAreas.FirstOrDefault.AxisX.LabelStyle.Format = "{0:0.0}" 'sets the format of labels to 1dp
AccelerationChart.ChartAreas.FirstOrDefault.AxisY.LabelStyle.Format = "{0:0.000}"
End Sub