While driving a sports car 20 m/s down a four-lane highway, a driver comes up behind a slow-moving dump truck and decides to pass it in the left-hand lane. If the driver can accelerate at 5 m/s2, how long will it take for him to reach a speed of 40 m/s?

Question

While driving a sports car 20 m/s down a four-lane highway, a driver comes up behind a slow-moving dump truck and decides to pass it in the left-hand lane.  If the driver can accelerate at 5 m/s2, how long will it take for him to reach a speed of 40 m/s?

oobleck · Answer

he gains 5m/s every second So, how long to gain 20 m/s? (40-20)m/s / 5m/s^2 = 4s