Question

A runner ran the marathon (approximately 42.0 km) in 2hours and 57 min. What is the average speed of the runner inm/s?

a. 124 m/s
b. 3.95 m/s
c. 14.2 x 10³ m/s
d. 14.2 m/s

Answer 1

The average speed of the runner is calculated by converting the marathon distance to meters and the running time to seconds, then dividing the distance by the time. The average speed is approximately 3.95 m/s.

Step-by-step explanation:

To calculate the average speed of the marathon runner in meters per second (m/s), we first need to convert the total running time from hours and minutes to seconds. The runner completed the marathon in 2 hours and 57 minutes, which is equal to (2 × 60 + 57) minutes or (120 + 57) minutes, which is 177 minutes. To convert this to seconds, we multiply by 60, giving us 177 × 60 = 10620 seconds.

Next, we convert the marathon distance from kilometers to meters. Since 1 km is equivalent to 1000 m, the distance in meters is 42.0 km × 1000 m/km = 42000 m.

The average speed is then calculated by dividing the total distance by the total time: Average speed = Total distance / Total time = 42000 m / 10620 s ≈ 3.95 m/s.

Therefore, the correct answer to the student's question is:

• b. 3.95 m/s

Answer 2

The average speed of the runner in m/s is 3.95 m/s.

Step-by-step explanation:

To find the average speed of the runner, we need to convert the time and distance to the same units. We know that 1 hour is equal to 3600 seconds. So, the time taken by the runner is 2 hours, 57 minutes, and 12 seconds, which is equal to 2*3600 + 57*60 + 12 = 10632 seconds. The distance ran by the runner is approximately 42.0 km, which is equal to 42000 meters.

Now, we can calculate the average speed using the formula: average speed = distance / time. Substituting the values, we get average speed = 42000 / 10632 = 3.95 m/s.

Therefore, the average speed of the runner is 3.95 m/s, making option b the correct answer.