Question

velocitt of body is changes from 18 km/hr to 90 km/hr in 10 sec calculate acceration in body​

Answer 1

Given:-

• $\sf{Initial Velocity (u) = 18km/hr = (18) \times \dfrac{5}{18}m/s= 5m/s}$
• $\sf{Final Velocity (v) = 90km/hr = (90) \times \dfrac{5}{18}m/s = 25m/s}$
• $\sf{Time = 10 sec}$

To find:-

• Acceleration of the body.

Solution:-

$\sf{u = 5 m/s}$

$\sf{v = 25 m/s}$

$\sf{t = 10 sec}$

$\sf{From\: The\: 1st\: equation\: of\: motion:-}$

$\sf{v = u + at}$

$\sf{=> v - u = at}$

$\sf{=>a = \dfrac{v-u}{t}-------->(i)}$

$\sf{Substituting \:the \:values\: of \:v,\: u\: and\: t\: in\: eq.(i)}$

$\sf{a = \dfrac{25-5}{10}}$

$\sf{a = \dfrac{20}{10}}$

$\sf{a = 2\: m/{s}^{2}}$

$\sf{Therefore\: the\: acceleration \:of \:the \:body\: is\: 2\:m/{s}^{2}}$

Important note:-

• $\sf{To\: convert\: km/hr\:into\: m/s\: multiply\: the \: unit\: with\: \dfrac{5}{18}}$
• $\sf{To\:convert\:m/s\: into\: km/hr\: multiply\: the \:unit\: with \: \dfrac{18}{5}}$

Answer 2

Answer:

acceleration= Change of velocity / time

a=v-u/t

given,v=90km/h=25m/s

u=18km/h=5m/s

t=10sec

now,a=(25-5)/10

=20/10

=2m/s²