please some one help me physic question!!!!?

Question

A particle leaves its initial position X0 at time t = 0,moving in the positive x direction with speed V0 but undergoing acceleration of magnitude a in the negative x direction.Find expression for a) the timw when it returns to the position X0 and b) its speed when pass that point

Answer 1

Start with

x = x0 + v0 t -1/2 a t^2

When x = x0 then x0 = x0 +v0 t1 -1/2 a t1^2

so 0 = v0 - 1/2 a t1 ---> t1 =2*v0/a

Now speed = v = -at + v0 let t = t1

v = -a t1 + v0 =-a * 2*v0/a +v0 = -v0

Answer 2

Simple X=(1/2)A*t^2+V0*t+X0
X = Distance
A = Acceleration
V0 = Initial Velocity
X0 = Initial Distance

a) 0=-(1/2)A*t^2+V0*t
b) 0>-(1/2)A*t^2+V0*t

Answer 3

what the hell is this