The force acting in the case is the thrust upwards and the weight of pallet downwards. Weight is force due to gravity and can be calculated by multiplying the mass X 9.8.
The resultant force on each pallet can be derived by
R = Thrust - weight.
Acceleration the speed increases each second. It can be calculated using the equation.
Accleartion = resultant force ( Newton ) / mass (kg).
Suppose your pallet weight is 50 grams and the thrust or force is 5N for 1 sec.
To find weight 50 gms needs to be changed to kg ( devided by 1000kg ). This gives mass of 0.050kg.
Weight is mass X 9.8 = 0.49 N
The resultant force is the thrust - Weight : 5 N - 0.49 = 4.51N.
Acceleration = resultant force devided by mass = 4.51 / 0.050 = 90m/ s.