Give an example of a motion where x > 0, v < 0, a > 0 at a particular instant.


Hint: Velocity, v = dxdt  and acceleration, a = dvdt.
Step 1: Let the motion is represented by

                        x(t) = A+Beγt                            ...i
Where             A>B and γ>0
Step 2: Calculate velocity
Now velocity, v(t) = dxdt = Bγeγt
Step 3: Calcuate acceleration
Acceleration, a(t) = dvdt = 2eγt

Step 4: At any time t

Suppose we are considering any instant t, then from Eq. (i), we can say that
x(t) > 0 v(t) < 0 and a > 0.