Avehicle accelerates from 0 to 30 m/s in 10 seconds on a
straight road, then travels 15 seconds at a constant velocity
next it slows down, coming to a stop in 5 seconds. the car
waits 10 seconds, and then backs up for 5 seconds
accelerating from 0 to -10 m/s draw a graph showing the
vehicle's velocity vs time by following these steps
what is the velocity of the vehicle at 0 seconds?
m/s

The velocity of the vechicle at 0 s is 0 m/s

Explanation:

The Velocity vs. Time graph of this situation is shown in the attached image. As we can see, we have five segments:

1) When the vehicle accelerates from 0 to 30 m/s in 10 seconds, which means at 0 seconds the vehicle's velocity was 0 m/s. In addition, as the vehicle goes from zero to a positive velocity, we have a positive slope.

2) Then the vehicle travels for 15 seconds at a constant velocity, that is why we do not have a slope in this section, since the vehicle kept its 30 m/s.

3) The vehicle comes to a stop in the next 5 seconds, that is why we observe an abrupt change in the graph and a negative slope.

4) The car  waits 10 seconds in that stop, again we have a line with no slope

5) Finally, the car accelerates from 0 to -10 m/s in the next 5 seconds. This means the car changed its direction.

explanation:

newton's third law, for every action there is an equal and opposite reaction.

there are no contact forces mentioned on the list of choices that you've provided.