Question

The coordinates of a particle moving in the \( x \)-\( y \) plane are given by: \[x = 2 + 4t, \quad y = 3t + 8t^2.\]The motion of the particle is:

• A. non-uniformly accelerated.
• B. uniformly accelerated having motion along a straight line.
• C. uniform motion along a straight line.
• D. uniformly accelerated having motion along a parabolic path.

Answer 1

The Correct Option is D

Velocity Component Calculation:

For \(x = 2 + 4t\):

\[ \frac{dx}{dt} = v_x = 4 \]

For \(y = 3t + 8t^2\):

\[ \frac{dy}{dt} = v_y = 3 + 16t \]

Acceleration Component Calculation:

The acceleration in the \(x\)-direction \(a_x\) is:

\[ \frac{d^2x}{dt^2} = a_x = 0 \]

The acceleration in the \(y\)-direction \(a_y\) is:

\[ \frac{d^2y}{dt^2} = a_y = 16 \]

The particle exhibits constant acceleration \(a_y = 16\, \text{m/s}^2\) along the \(y\)-axis and no acceleration along the \(x\)-axis.

Determine Trajectory:

To determine the particle's path, express \(y\) as a function of \(x\) by eliminating \(t\) from the given equations.

From \(x = 2 + 4t\):

\[ t = \frac{x - 2}{4} \]

Substitute this expression for \(t\) into the equation for \(y\):

\[ y = 3\left(\frac{x - 2}{4}\right) + 8\left(\frac{x - 2}{4}\right)^2 \]

Upon simplification:

\[ y = \frac{3}{4}(x - 2) + 8 \times \frac{(x - 2)^2}{16} \] \[ y = \frac{3}{4}(x - 2) + \frac{1}{2}(x - 2)^2 \]

This equation, being quadratic in \(x\), signifies that the particle follows a parabolic path.

Summary:

The particle's motion is uniformly accelerated, characterized by a parabolic trajectory, consistent with Option (4).