Question

a particle moves along the x-axis so that at time t >(or equal to) 0 its position is given by x(t)=2t^3 - 21t^2 + 72t-53. At what time t is the particle at rest?

Answer 1

Particle is at rest when Velocity = 0

Answer 2

V = X ' ( t ) = 6t^2 - 42t + 72 = 0

Answer 3

V = t^2 - 7t + 12 = 0

Answer 4

Solve for t:
t1 = 3
t2 = 4
Particle is at rest at t = 3 and t = 4.
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