Please help me with A and B

A 0.75 kg cart moves along a straight, horizontal track. The graph below shows the cart's velocity (V.) as a function of time (t). Velocity is given in units m/s, and time is given in seconds. Use this graph to answer questions a - e. a) Indicate every time (t) for which the cart is at rest. The cart is at rest when t=0 and when t=20 b) Indicate every time interval for which the speed (magnitude of velocity) of the cart is increasing. Use evidence from the graph to justify your answers. V, (m/s) Velocity vs. Time On a Straight Horizontal Track 0.8 0.3 it(s) -0.2 -0.7 -1.2