Please help! Physics questions?

Question

An object with a mass of 50kg is being dragged along a horizontal floor by a horizontal force of 30N. If the friction force opposing the motion is a steady 20N, what is the acceleration of the body?

Answer 1

Use the equation F = m * a

(force = mass * acceleration)

The force used to accelerate the object is 30N - 20N = 10N

So a = F/m = 10/50 = 0.2 m/s2