Determine the mass of a body that, under the action of a force of 100N, moves on a horizontal surface, increasing its speed

Determine the mass of a body that, under the action of a force of 100N, moves on a horizontal surface, increasing its speed from 1m / s to 10m / s for 3s. The friction coefficient is 0.2.

The body moves with acceleration, therefore we apply Newton’s 2 law: Sum of forces = m * a. Regarding the axis OX 2 law: Fmotion – F friction = m * a. We find the acceleration by the formula (V final-V initial) / t (time) = 3 m / s ^ 2, F friction = mu (friction coefficient) * support reaction force = mu * mg
We get: F-mu * mg = m * a
100-0.2 * 10 * m = 3m
m = 20 kg
Answer: 20