Hello,
I understand the issue you are facing where the velocity is not a 1D array. To make velcoity a 1D array please use the dot(.) operator.
For Example:
for the following statement the output is a double datatype
>>v0 = ((s-s0)+(1/2).*(981/100).*t.^2)/t;
V0 can be changed to a 1D array using the following command using dot operator
>>v0 = ((s-s0)+(1/2).*(981/100).*t.^2)/.t;
This should solve the issue you are facing.