A particle is moving along a straight line whose velocitydisplacement graph is as shown in Fig. $6.2 .$ What is the acceleration when the displacement is $3 \mathrm{~m}$ ?
a. $4 \sqrt{3} \mathrm{~m} / \mathrm{s}^{2}$
b. $3 \sqrt{3} \mathrm{~m} / \mathrm{s}^{2}$
c. $\sqrt{3} \mathrm{~m} / \mathrm{s}^{2}$
d. $4 / \sqrt{3} \mathrm{~m} / \mathrm{s}^{2}$
Fig. $6.2$