Question

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 1

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 = (\Delta V)/(\Delta t)`

`a = (-8-(5))/(20-10)`

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 = (18)/(1.30)`

t = 13.85 s