[单选题]
A cart starts from rest andq 2bkxa0r81 3cmq ir5)p i demkmejzm+bh+ 950 ac5 :wwx :h0:xjqspvbd,wiw,4l celerates at $4.0 \; m/s^2$ for 5.0 s, then maintain that velocity for 10 s, and then decelerates at the rate of $2.0 \; m/s^2$ for 4.0 s. What is the final speed of the car?
