All Exams Test series for 1 year @ ₹349 only
Question

A body moves 6 km towards the east in 1 hour and then 8 km towards the west in the next 1 hour. The average velocity of the body for the whole journey is ___________ .

The correct answer is
1 km/h west

Calculating Average Velocity for Displacement Journey

Average velocity is defined as the total displacement divided by the total time taken.

The formula is:

$ \vec{v}_{avg} = \frac{\Delta \vec{x}}{\Delta t} $

Where:

  • $ \vec{v}_{avg} $ is the average velocity
  • $ \Delta \vec{x} $ is the total displacement
  • $ \Delta t $ is the total time

Determining Total Displacement

We need to consider the direction of movement. Let's assume the eastward direction is positive (+) and the westward direction is negative (-).

  • Movement 1: 6 km towards the east = $+6$ km
  • Movement 2: 8 km towards the west = $-8$ km

Total Displacement $ \Delta \vec{x} $:

$ \Delta \vec{x} = (+6 \text{ km}) + (-8 \text{ km}) = -2 \text{ km} $

The negative sign indicates the total displacement is towards the west.

Calculating Total Time

The total time is the sum of the time taken for each part of the journey.

  • Time 1 = 1 hour
  • Time 2 = 1 hour

Total Time $ \Delta t $:

$ \Delta t = 1 \text{ hour} + 1 \text{ hour} = 2 \text{ hours} $

Finding the Average Velocity

Now, we can calculate the average velocity using the total displacement and total time.

$ \vec{v}_{avg} = \frac{-2 \text{ km}}{2 \text{ hours}} = -1 \text{ km/h} $

Since the result is negative, the average velocity is 1 km/h towards the west.

Was this answer helpful?

Important Questions from Speed and Velocity

  1. The given equation provides the property of the motion of an object, traversing a circular path. What is ‘v’ in this equation?

    ac = v2/R

  2. The basic unit of speed of an object is ______.

  3. Which of the following quantities specifies its speed with direction?

  4. Which of the following represents non-uniform linear velocity?
  5. Which of the following describes the nature of the average speed?
Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App