The coordinates of a moving particle at any time $t$ are given by $x = \alpha t^3$ and $y = \beta t^3$. The speed of the particle at time $t$ is given by

Which two motions are considered to be combined for motion in a plane?

The position vector of a particle changes with time according to the relation $\vec{r}(t) = 15t^2 \hat{i} + (4 - 20t^2) \hat{j}$. What is the magnitude of the acceleration at $t = 1 \ s$?

$A$ particle starts from the origin at $t=0$ with a velocity of $10 \hat{j} \text{ ms}^{-1}$ and moves in the $x-y$ plane with a constant acceleration of $(8 \hat{i} + 2 \hat{j}) \text{ ms}^{-2}$. At an instant when the $x$-coordinate of the particle is $16 \text{ m}$, the $y$-coordinate of the particle is: (in $\text{ m}$)

$A$ particle moves in the $x-y$ plane with velocity $\vec{v} = a\hat{i} + bx\hat{j}$,where $a$ and $b$ are constants. If the particle was initially at the origin,find the equation of its trajectory.

The position of a particle is given by $\vec{r} = 3.0 t \hat{i} - 2.0 t^{2} \hat{j} + 4.0 \hat{k} \; m$,where $t$ is in seconds and the coefficients have the proper units for $\vec{r}$ to be in metres.
$(a)$ Find the velocity $\vec{v}$ and acceleration $\vec{a}$ of the particle.
$(b)$ What is the magnitude and direction of velocity of the particle at $t = 2.0 \; s$?