Question

A car accelerates from rest at a constant rate of 2 m/s2 for some time. Then it retards at a constant rate of 4 m/s2 and comes to rest . It remains in
motion for 6 seconds
(A) It's maximum speed is 8 m/s
(B) It's maximum speedis 6 m/s
(C) Itis travelled a total distance of 24 m
(D) It is travelled a total distance of 18 m​

Answer 1

$\sf\small\underline \green{Given:-}$

$\bullet \: \sf a \: = 8 \: \dfrac{m}{s} ^{2}$

$\bullet \sf \: u = 0 \dfrac{m}{s} ^{2}$

$\sf\small\underline \green{Find:-}$

• Correct option.

$\sf\small\underline \green{Solution:-}$

$\rightarrow \sf \: v_{o} = 2 t_{1} = 2 t_{1} \: . \: v_{4} = 2_{2} \: t_{2} = 4 _{2}$

$\rightarrow\sf \: t_{(1)} + t_{(2)} = 6$

$\rightarrow\sf \: \frac{ v_{o} }{2} + \frac{ v_{o} }{4} = 6$

$\rightarrow\sf v_{(o)} = 8$

Now,

Total distance travelled

$\rightarrow\sf \: u + a(n - 12)$

$\rightarrow\sf0 + 8( \frac {5 + 1}{2} )$

Hence the distance covered is

$\dashrightarrow\sf \fbox \red{24m}$

So, correct answer is ( c )