Question

A block of mass 2kg placed on a long frictionless horizontal table is pulled horizontally by a constant force F. It is found to move 10 m in the first two seconds find the magnitude of F

Answer 1

It is frictjonless so accelerates at a constant rate, a. They must want you to assume it starts from rest. The acceleration rate a is then given by
10 = (a/2)t^2 = 2a
a = 5 m/s^2

Now use F = M a for the force.

F = 10 N