Question

A car increases its speed with uniform rate from 20 km/h to 50 km/h in 10 seconds. Find the average speed of the car.​

Answer 1

Answer:

19.3 m/s is the answer hope it helps

Answer 2

Given:

A car increases its speed with uniform rate from 20 km/h to 50 km/h in 10 seconds.

To find:

Average Speed of car?

Calculation:

USE v_(avg) = (u+v)/2 directly ONLY IN MCQs, NOT IN SCHOOL/BOARD EXAMS !!

FOR SCHOOL EXAMS, follow this method:

$\rm v_{avg} = \dfrac{displacement}{time}$

$\rm \implies \: v_{avg} = \dfrac{s}{t}$

$\rm \implies \: v_{avg} = \dfrac{ut + \dfrac{1}{2}a {t}^{2} }{t}$

$\rm \implies \: v_{avg} = u + \dfrac{1}{2}a t$

$\rm \implies \: v_{avg} = \dfrac{2u + at}{2}$

$\rm \implies \: v_{avg} = \dfrac{u + (u + at)}{2}$

$\rm \implies \: v_{avg} = \dfrac{u + v}{2}$

AFTER THIS DERIVATION, you can put the values:

$\rm \implies \: v_{avg} = \dfrac{20 + 50}{2}$

$\rm \implies \: v_{avg} = \dfrac{70}{2}$

$\rm \implies \: v_{avg} = 35 \: km/hr$

So, average velocity is 35 km/hr.