How Can Particle Trajectory and Motion Dynamics Be Analyzed in a Planar System?

AI Thread Summary
The discussion focuses on analyzing the motion of a point particle in a planar system, defined by the trajectory r(t) = R [θ(t)]^3/2, with θ(t) = 1/2 α t^2 and α = 1 s^-2. Participants are asked to sketch the trajectory, compute specific times when the radial and tangential components of velocity coincide, when acceleration is purely tangential, and when radial acceleration is twice the tangential acceleration. There is a request for simplified explanations to aid understanding, particularly regarding the sketching of the trajectory and the implications of a constant |R|. The conversation emphasizes the need for clarity in polar coordinate equations and their physical interpretations.
jackiemoon
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Hi,

Can anybody help with the following:

A point particle moves in a plane with trajectory given by r(t) = R [θ (t)]^3/2, where R is a constant.

The angle θ in radians increases in time according to the equation θ (t) = 1/2 α t^2,
where α is a constant whose numerical value is α = 1 s^-2.

a. Sketch the trajectory of the particle.
b. Compute the time t > 0, if any, for which the radial and tangential components of the velocity of the particle coincide.
c. Compute the time t > 0, if any, for which the acceleration of the particle is purely tangential.
d. Compute the time t > 0, if any, for which the radial acceleration of the particle is twice its tangential acceleration.

I really am struggling with this question. I'm not even sure about sketching the trajectory, which is usually the least I can do in these type of questions! Can anybody help and explain it in really simple terms. Thanks for any help with this.
 
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What you have is an equation in polar coordinates don't you?

And if |R| is constant, it is described how?
 
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