A 6kg crate originally at rest is pulled to the right along a horizontal plane with a constant horizontal force of 12N.
a)find the velocity of the crate once it has moved 3m on the frictionless horizontal plane.
b)Find the velocity of the crate once it has moved on the horizontal plane which is now not frictionless and has a kinetic frictional force of 8N between the crate and the plane.