Question

What force is needed to accelerate a child on a sled at 1.25 m/s² is the total mass of the child and sled is 60 kg?

Answer 1

Newton's 2nd law of motion:  (Honestly, if you don't
remember this by now, you're going to have problems.)

                           Force  =  (mass) x (acceleration).

                                        =  (60 kg) x (1.25 m/s²)

                                        =          90  kg-m/s²

                                        =          90 Newtons .