A student pushes a block from rest across a frictionless surface while the block is in front of a motion detector for 3 seconds. The block first speeds up for the 1st second, then moves at constant velocity for the 2nd second, and finally slows down during the final second. Which statement best explains the motion of the block using Newton's 1st Law?
There is a net force on the block during the 2nd second as a net force keeps the motion constant.
There is a net force on the block during the 3rd second as a net force keeps the motion constant.
There is no net force on the block during the 2nd second as zero net force keeps the motion constant.
There is no net force on the block during the 3rd second as zero net force causes the motion to accelerate.