Physics
Physics
Problem
A cyclist rides along a straight east–west road in two stages. In the first stage she covers 12 km due east in 30 min. In the second stage she rides another 8 km due east in 20 min. a. (a) Calculate the total distance travelled and the total time taken. b. (b) Find the average speed for the whole trip. c. (c) Determine the magnitude and direction of the average velocity for the entire motion.Intuitive explanation
The key here is distinguishing between average speed (total distance ÷ total time) and average velocity (total displacement ÷ total time). Since both stages go in the same direction, displacement and distance are the same, but you need to add up all the distance and all the time across both stages to find the true average. Don't just average the two speeds from each stage—that's a common trap.
Intuitive explanation
The key here is distinguishing between average speed (total distance ÷ total time) and average velocity (total displacement ÷ total time). Since both stages go in the same direction, displacement and distance are the same, but you need to add up all the distance and all the time across both stages to find the true average. Don't just average the two speeds from each stage—that's a common trap.