At t= 10 s, a particle is moving from left to right with a speed of 5.0 m/s. at t=20 s, the particle is moving right to left with a speed of 8.0 m/s. assuming the particle's acceleration is constant, determine (a) its acceleration,
(b)its initial velocity, and
(c) the instant when its velocity is zero.

Answer

given,

at time t = 10 s  moving from left to right speed of particle = 5 m/s

at t = 20 s  moving from right to left speed of particle is = 8 m/s

a) acceleration

            a = -1.3 m/s²

b) using equation of motion

      v = u + at

      5 = u - 1.3 × 10

      u = 5 + 13

      u = 18 m/s

c) v = u + at

   0  = 18 - 1.3t

     t = 13.85 s

where are the vectors ?