Question

3 5 6 Question 1 What is your answer? The speed vs. time graph shows the motion of a person driving a car Why is this your answer? 60 speed (m/min) 20 time (min) -20 Which is the correct answer? 20 30 Why is this the correct answer? How much did the car's speed change in the time interval from 15 and 20 minutes? The speed increased by 40 m/min. B The speed decreased by 40 m/min c The speed increased by 20 m/min. The speed decreased by 20 m/min.

Answer 1

From the graph, the speed of the car at t=15m is 60 m/min, and the speed of the car at t=20m is 40 m/min. The change in velocity is given by:

`\begin{gathered} \Delta v=40m/\min -60m/\min \\ =-20m/\min \end{gathered}`

Therefore, the speed decreased by 20 m/min.