Question

“A train of mass 120,000 kg is moving with velocity of 10m/s and is acted upon by a forward force of 7000 N due to engine and frictional force of 750 N. What will be the velocity of the train after 1,000 seconds?”

Answer 1

The Newton's second law says

$$a=\frac{F_{net}}{m}=\frac{7000-750}{120000}=0.052\:\rm m/s^2$$

The final speed

$$v_f=v_i+at\\ =10+0.052*1000=62\:\rm m/s$$