Answer:
t=4c/3d. For t>0
Step-by-step explanation:
Since we have to find an expression for the time t > 0 when the particle is moving parallel to x-axis, that implies there is no y component of velocity.
Hence,
Y component of velocity=0
We will find the y component of velocity via differentiating y-coordinate.
y= 2ct2−dt3
Differentiating y coordinate,
dy/dt = 4ct - 3dt²
Since y component of velocity is 0.
4ct - 3dt²=0
(4c - 3dt)t = 0
This is valid
when t=0 and when 4c-3dt=0.
4c=3dt
t=4c/3d
Since we are only asked for t>0, there is only one instant when the particle is moving int x-direction so the right answer is:
t =4c/3d
