The graph below shows a cars distance from the starting line

The graph below shows a car\'s distance from the starting line (in feet) in terms of the number of seconds, t that have elapsed since the start of the race What is the average speed of the car as t increases from 10 to 20 seconds? What is the average speed of the car as t increases from 20 to 30 seconds? What is the average speed of the car as t increases from 30 to 40 seconds? What is the average speed of the car as t increases from 40 to 50 seconds? For consecutive intervals of time, the average speed of the car is Thus the speed of t he car is over the first 50 seconds of the race.

Solution

a) average speed from 10 to 20 seconds

avearge speed = total distance / total time

average speed = 7 / 10 = .7 feet / sec

b) average speed from 20 to 30 seconds

distance covered between 20 to 30 seconds = 10 feet

time = 10 seconds

speed = 10/10 = 1 feet / sec

c) average speed from 30 to 40 seconds

distance travelled = 40 - 20 = 20 feet

time = 10 seconds

speed = 20 / 10 = 2 feet / sec

d) average speed from 40 to 50 seconds

distance travelled = 90-40 = 50 feet

time = 10 seconds

speed = 50/10 = 5 feet / second