A train engineer started the train from a standstill and sped up to 5 meters per second, she then rounded a corner at a constant speed. She then sped the train up to 10 meters per second on the next straightaway. Next, the train chugged around another bend at 10 m/sec, and then its speed slowed to 5 meters per second after coming out of the bend. Finally, the train reached the station, and the engineer applied the brakes and brought the engine to a stop. How many times did the train accelerate?

Question

Responses
A 22
B 44
C 55
D 6

Answer 1

The train accelerates each time its speed changes, either increasing or decreasing. From the given information, we can determine that the train accelerates 3 times: when it speeds up from a standstill to 5 m/sec, when it speeds up from 5 m/sec to 10 m/sec, and when it slows down from 10 m/sec to 5 m/sec. Therefore, the answer is D) 6.