Question

question 6 of 10
to a stationary observer, a bus moves north with a speed of 10 m/s. a man inside walks toward the back of the bus with a speed of 0.4 m/s relative to the bus. what is the velocity of the man according to a stationary observer?
a. 9.6 m/s north
b. 0.4 m/s north
c. 10 m/s north
d. 10.4 m/s north

Explanation:

Step1: Define velocities

Let the velocity of the bus relative to the stationary observer be $v_{b}=10\ m/s$ (north - positive direction) and the velocity of the man relative to the bus be $v_{m - b}=- 0.4\ m/s$ (negative as he moves towards the back of the bus).

Step2: Use relative - velocity formula

The velocity of the man relative to the stationary observer $v_{m}$ is given by the formula $v_{m}=v_{b}+v_{m - b}$.
Substitute the values: $v_{m}=10+( - 0.4)$.
$v_{m}=10 - 0.4=9.6\ m/s$. The positive sign indicates the direction is north.

Answer:

A. 9.6 m/s north