Question

A train travels in a straight line at 15.0 m/s for 2 km, then at 30.0 m/s for another 2 km. Part A Part complete Is the average speed of the train greater than, less than, or equal to 25 m/s? Is the average speed of the train greater than, less than, or equal to 25 ? The average speed of the train is less than 25 m/s. The average speed of the train is greater than 25 m/s. The average speed of the train is equal to 25 m/s. Previous Answers Correct Part B Verify your answer to Part A by calculating the average speed. Express your answer to three significant figures and include the appropriate units.

Answer 1

Answer:

The average speed is 20 m/s

Explanation:

To calculate this we need to divide the distance in meters (2km + 2km = 2000m + 2000m = 4000 m ) times the speed (in seconds) the train was traveling

using x = t * v we can calculate the time for each part

2000m = t₁ * 15 m/s

2000m / 15 m/s  = 133.33333333... s = t₁

2000m = t₂ * 30m/s

2000m / 30 m/s = 66.6666666... s = t₂

then

$\frac{2000m+2000m}{66.666666s+133.33333s} = \frac{4000m}{200s} =20m/s$