Multiple choice

A train is moving slowly on a straight track with a constant speed of $2m/s.$ A passenger in that train starts walking at a steady speed of $2m/s$ to the back of the train in the opposite direction of the motion of the train so to an observer standing on the platform directly in from of that passengers, the velocity of the passenger appears to be:

  1. $4\;ms^{-1}$
  2. $2\;ms^{-1}$
  3. $4\;ms^{-1}$ in the opposite direction of the train

  4. zero
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The velocity of the passenger relative to the ground is the vector sum of the train's velocity and the passenger's velocity relative to the train. Since the train moves at 2 m/s and the passenger walks at 2 m/s in the opposite direction, the resultant velocity is 2 - 2 = 0 m/s.

AI explanation

Using the relative velocity formula for opposite motions, the velocity of the passenger with respect to the observer on the platform is the difference between the velocity of the train and the velocity of the passenger. The train is moving forward at 2 m/s and the passenger is walking toward the back at 2 m/s, so the relative velocity is 2 m/s minus 2 m/s. This calculation gives the apparent velocity as zero.

Keep practicing — related questions