The given graph shows how the speed of a car changes with time: What is the maximum speed attained by the car ?

As shown in the figure the point O is showing the beginning of time. The x-axis shows the time and the y-axis shows speed. As shown in the figure, after 3 hours from beginning the car attains its maximum speed of 35 km / h corresponding to point B and it remains constant till 8 s .

The given graph shows how the speed of a car changes with time: Which part of the graph shows zero acceleration ?

The acceleration of the car is zero in the BC part of the graph. It is so because the slope of the graph in this region is zero. Acceleration of a body is defined as the rate of change of its velocity with time. Hence, if change in velocity is zero then acceleration is also zero.

The given graph shows how the speed of a car changes with time: Which part of the graph shows varying retardation ?

Retardation is also called negative acceleration. In the CD part of the graph, velocity of the car is decreasing non-uniformly with time which shows the varying retardation. We can also say that the slope of the graph is negative or not constant from 8 s to 10 s .

The given graph shows how the speed of a car changes with time: Find the distance travelled in first 8 hours.

From graph, Velocity of car at point A , v A = 10 km h . Velocity of car at point B and C , v B = v C = 35 km h . Let S be the total distance travelled by the car first eight hours and t n represent the time of n hours. Therefore, S = Area of trapezium under A B F 0 + area of rectangle under B C E F ⇒ S = 1 2 v A + v B × t 3 + v C × t 8 - t 3 ⇒ S = 1 2 10 + 35 × 3 + 35 × 8 - 3 ⇒ S = 1 2 × 45 × 3 + 35 × 5 ⇒ S = 67 . 5 + 175 ⇒ S = 242 . 5 km