A body starts from the origin and moves along the x-axis with velocity v = 4t³ - 2t, where t is in second and v in m s⁻¹. What is its acceleration when it is 2 m from the origin?
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Question

A body starts from the origin and moves along the x-axis with velocity v = 4t³ - 2t, where t is in second and v in m s⁻¹. What is its acceleration when it is 2 m from the origin?

G1 Physics · Accepted Answer

v=4t³-2t, so x=∫vdt=t⁴-t² (x=0 at t=0). Set x=2: t⁴-t²-2=0 ⇒ t²=2. Acceleration a=dv/dt=12t²-2=24-2=22 m s⁻². Hence option B.