a particle starts from rest and has an acceleration of 4m/s 2 for 20 seconds after that it travels for 30 seconds with constant speed and then undergoes a retardartion of 8m/s2. and come back to rest.the total distance covered

• 3parts to cover the distance:- s= s1+s2+s3
  part 1:
  v=u+at ; u=0,a=4,t=20
  => v=80 ; s1=ut+(1/2)at^2
  => s1= (1/2)*4*20*20
  => s1=800
  
  part2:- v becomes u now
  a=0
  so, v=u+at
  =>v=u=80
  s2=ut => 80*30=2400
  
  part3
  now particles comes back to rest hence v=0,u=80,a=-8
  v^2=u^2+2*a*s
  =>0=(-80)^2+(2*(-8)*s3)
  s3=400
  
  finally s=s1+s2+s3=800+2400+400=3600
  answer will be 3600 m.
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• Answer is 1 metre
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