A car starts from rest and accelerates at a constant rate travelling a distance of 210 m in 14.9 s. The car continues to accelerate at the same rate for an additional 199 m. What is the speed (in m/s) of the car after it has travelled the (210+199) m?
Under uniform acceleration,s=ut+1/2a*t^2,where s is displacement, u is initial velocity, t is time and a is acceleration.
Here,s=210 m, t=14.9 s,u=0 m/s(the car starts from rest)
=> a=210*2/(14.9*14.9)=1.8918 m/s2.
Also, under uniform acceleration, v^2=u^2+2*a*s, where v is final velocity, u is initial velocity, a is acceleration and s is displacement.
For the complete motion,s=210+199 m=409 m, u= 0 m/s, a=1.8918 m/s2.
=> v=39.34 m/s
So, required velocity=39.34 m/s
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