Title: Where is the cart being pushed?

Credits: by Riann (Author); source https://upload.wikimedia.org/wikipedia/commons/0/0e/Fhsst_rectmot15.png; licence CC BY-SA 3.0

Q: Identify the portion of the speed-time graph where the cart is being pushed.
A: The cart is pushed from about 0.5 s to 1.0 s, where the speed is changing. The cart moves on it's own from about 1.0 s to 3.5 s, where the speed is relatively constant.