A car accelerates uniformly in a straight line from rest at the rate of #2.3##m##/##s^2#. What is the speed of the car after it has traveled 55 m? How long does it take the car to travel 55 m?

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Answer 1 · 2018-06-07T06:19:54

The speed is #=15.91ms^-1#.
The time is #=6.92s#

The initial speed is #u=0ms^-1#

The acceleration is #a=2.3ms^-2#

The distance is #s=55m#

Aplly the equation of motion

#v^2=u^2+2as#

Therefore,

#v^2=0+2*2.3*55=253#

The speed is

#v=sqrt(253)=15.91ms^-1#

Apply the equation of motion

#v=u+at#

The time is

#t=(v-u)/a=(15.91-0)/2.3=6.92s#

Answer 2 · 2018-06-07T06:45:09

The speed of the car is root 253. The required time is root 47.82.

We know, #v^2 + u^2 = 2as#
u= o, a=2.3 #ms^-2#
So, #v^2=0^2+2*2.3*55#
#=># #v^2=253#
#=># #v= sqrt253#
#=>v=15.90# #ms^-1#

        Now,    v=u+at
      or   15.90=0+2.3t
       or           t=6.91 s