a motor car starts from rest and accelerates uniformly for 10s to a velocity of 20m/s it then runs - Physics - Motion In A Straight Line

Question

a motor car starts from rest and accelerates uniformly for 10s
to a velocity of 20m/s it then runs at a constant speed and is
finally brought to rest in 40m with a constant acceleration total
distance covered is 640m find the value of accelartion retardation
and total time taken

Kumar Prabhat · Accepted Answer

Acceleration a = final velocity-initial velocitytime
taken=20-010=2m/s2Distance travelled by motor car in first 10s
s=ut+12at2 , s=12×2×102=100mDistance travelled with
constant speed = 640m-100m=540m finally motor car comes to rest
means final speed here is zero let constant speed is u time given
is 40s retardation =-u40m/s2Also, 0-u2=2-u40×540 u=27m/s
constant speedTotal time taken is 50seconds

a motor car starts from rest and accelerates uniformly for 10s to a velocity of 20m/s. it then runs at a constant speed and is finally brought to rest in 40m with a constant acceleration. total distance covered is 640m. find the value of accelartion retardation and total time taken.