Chapter 8, Problem 8.38SP

Interpretation Introduction

Interpretation:

The kinetic energy of $1400\text{ kg}$ car moving at a speed of $115\text{ km/hr}$ and $12000\text{ kg}$ truck moving at $38\text{ km/hr}$ have to be compared.

Concept Introduction:

• Energy refers to the capacity to do work whereas work refers to transfer of energy from one object to another or one system to another system.  Work also refers to conversion of energy from one form to another form as we know energy can neither be created nor be destroyed.
• SI unit of energy is joule.
• Kinetic energy refers to energy possessed by moving object. It is denoted by $E_K$ and calculated as –

$E_K=\frac{1}{2}m{v}^2$

Where,

 $m=mass,\text{ v = velocity}$