Question

A body moves in straight line and covers first half of the distance with speed 5 m/s and second half in two equal halves with speed 4m/s and 3m/s respectively. The average velocity of the body is

Answer 1

Let the total distance covered by the body is 2d so distance of each half is "d"

now the time taken by the body to cover first half will be

$t = \frac{d}{v}$

$t_1 = \frac{d}{5}$

now for the next half it covers the total distance in two equal time intervals

so we can say

$d = v_1*\frac{t}{2} + v_2*\frac{t}{2}$

$d = (4 + 3)*\frac{t}{2}$

$t_2 = t = \frac{2d}{7}$

now the formula of average speed is given by

$v_{avg} = \frac{total \. distance}{total \. time}$

$v_{avg} = \frac{2d}{t_1 + t_2}$

$v_{avg} = \frac{2d}{\frac{d}{5} + \frac{2d}{7}}$

$v_{avg} = \frac{70}{17}$

$v_{avg} = 4.12 m/s$

so the average speed of whole journey will 4.12 m/s

Answer 2

Answer:

Answer is 4.12 m/s

Explanation:

First we should find the time taken by the body to cover the distances and then we should use the average velocity formula.