When does the car have the highest velocity? when does the car have approximately zero acceleration? how would you find the displacement of the car from this graph? (the graph below shows the speed of a car as it drives along a racetrack)

-- This is a GRAPH of velocity.  Wherever the graph is highest, that's when the velocity is highest.  Find the highest point on the graph, and look straight down under it to find the time.

-- The slope of the velocity graph at every point is the acceleration.  Acceleration is zero wherever the slope of the graph is zero.  Think about laying a ruler on the graph at every point, and look for a point on the graph where the ruler would be horizontal (slope of zero).

-- The total distance the car has covered at any time is the area under the graph from the y-axis up to that time.

The graph can't tell us the car's displacement because there's no information in the graph that shows the direction the car is going at any time.  The graph is really a speed graph, not a velocity graph.

i) Highest velocity at t= 2 s

ii) acceleration is zero at t = 2 s

iii) displacement of the car is area under velocity time graph

Explanation:

As we know that the given graph is for velocity time graph

so here maximum velocity velocity is reached when graph will achieve at its maximum height

So it will be at t = 2 s

As we know that acceleration is rate of change in velocity

so we can say

so it is slope of velocity and time graph

so here slope will be zero at t= 2 s

now for displacement we know that

so here we have

so area of the graph under velocity and time graph will give us displacement of the graph