Question

what force accelerates a 20kg mass at 2 meter per second square on a frictionless surface

Answer 1

we know that force is equal to mass x acceleration so
F=m×a
F=20×2
F=400N

Answer 2

We know that-
F=ma
F=20kg*2m/s^2
F=40kgm/s^2
or
F=40N