An object was accelerated with a force of 150 N from rest to a velocity of 10m/s in 5 sec. the force of friction opposing the object was 100N. What was the object's mass

Force = (mass) x (acceleration)

Mass = (force) / (acceleration)

There was 150N of force in one direction and 100N of 'force' in

the other direction. The net force on the object was (150 - 100) = 50N.

Acceleration = (change in speed) / (time for the change)

= (10 m/s) / (5s) = 2 m/s²

Mass = (net force) / (acceleration) = (50 N) / (2 m/s²) = 25 kilograms