15. The position of a particle moving along x-axisgiven "by χ = (-2t3

1.	15. The position of a particle moving along x-axisgiven "by χ = (-2t3 +3t2 + 5) m. Theacceleration of particle at the instant its velocitybecomes zero is
Answer» x = -2t³+3t²+5 dx/dt = v = -6t²+6t = 0 so, the time when v is 0,6t(1-t) = 0 => t = 0 or 1 sec and acceleration is dv/dt = -12t+6 so, value of a at t = 0 is = 6m/s²and when t = 1 is t = -6m/s²

15. The position of a particle moving along x-axisgiven "by χ = (-2t3 +3t2 + 5) m. Theacceleration of particle at the instant its velocitybecomes zero is

Answer»

x = -2t³+3t²+5 dx/dt = v = -6t²+6t = 0

so, the time when v is 0,6t(1-t) = 0 => t = 0 or 1 sec

and acceleration is dv/dt = -12t+6

so, value of a at t = 0 is = 6m/s²and when t = 1 is t = -6m/s²