Question

A body travels 20m in the first 4s and 15m in the next 4s. Calculate the average velocity

Answer 1

Answer:

4.375

Step-by-step explanation:

average velocity=Total distance traveled ÷total time taken

20+15÷4+4=35÷8=4.375

Answer 2

$\bold{First \: of \: all \: we mwill calculate \: it's \: acceleration}$

$\boxed{ \bold{ \red{S=ut+1/2at^2}}}$

$\bold{Now, 20m=2u+1/2a*4=2u+2a}$

$\rightarrow \: { 10m=u+a}$

$\rightarrow{a=10-u}$

$\bold{Now,48m= 6u+1/2a*36=6u+18a}$

$\bold{So,u+3a=8m}$

$\rightarrow{a=8-u/3}$

$\rightarrow{8-u/3=10-u}$

$\rightarrow{30-3u=8-u}$

$\rightarrow{22=2u}$

$\rightarrow{u=11m/s}$

$\rightarrow{a=-1m/s^2}$

$\bold{Now,total \: distance}$

$\bold{=11 \times 10+1/2 \times -1 \times 100=110–50=60}$

$\bold{Reqired \: distance=60–48=12}$