Motion of a Particle in x-y Plane: Calculations

In summary, at time 1.60 seconds, the y-coordinate of the particle is 8.27 meters, at time 1.90 seconds, the x-component of the velocity is 8.58 meters/second, at time 3.70 seconds, the magnitude of the acceleration is 8.58 meters/second2, and at time 3.80 seconds, the x-component of the acceleration is 8.58 meters/second2.
  • #1
Gjky424
2
0
The motion of a particle moving in a circle in the x-y plane is described by the equations: r(t)=8.27, Θ(t)=8.58t
Where Θ is the polar angle measured counter-clockwise from the + x-axis in radians, and r is the distance from the origin in m.
a)Calculate the y-coordinate of the particle at the time 1.60 s.


b)Calculate the x-component of the velocity at the time 1.90 s?


c)Calculate the magnitude of the acceleration of the particle at the time 3.70 s?


d)Calculate the x-component of the acceleration at the time 3.80s?


My teacher gave us a key to solve these but i can't make sense of it.

Part A
y = r(t)*sin(Θ(t)*t)

Part B:
vx = Θ*r*cos(Θ(t))

Part C:
ax= -(Θ^2)*r cos (Θ(t))
ay = -(Θ^2)*r sin (Θ(t))
a = sqrt(ax^2 + ay^2)

Part D:
ay = -(Θ^2)*r*sin(Θ(t))


I'm not sure what the difference is between Θ and Θ(t) & r and r(t)
 
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  • #2
1) At time t=0 , Θ(t)=0 , with time the r(t) remains the same becaus eit is indpendent of time. So the oarticle starts with Θ(t)=0 , and with time Θ(t) increases linearly with 't'.
So at some time t , the particle moves through an angle Θ(t)=8.58t.Put the value of t=1.6/1.9 seconds , therefore now the x\y-coordinate of the particle's position is the component of r(t) over x and y-axis respecticely.

You need to double differentiate r(t) for acceleration on x-axis and y-axis seperately and then calculate the resultant from these.

difference between Θ and Θ(t) & r and r(t)


Θ --- Symbol For Angle
Θ(t)--- Symbol For Time Dependent Angle (which changes with time)
r----- Symbol of arm length/radius of the particle's circle
r(t)----- Symbol for time-dependent radius , but here as you can see that r(t) has an expression independent of time , so it won't change with time.

BJ
 
  • #3
or you can take and use vectors. you have r(t) = 8.27 and ~(t) = 8.58t

take 8.58 * 1.6 and you get 13.728 rad

then you have a 2d vector [8.27, 13.728]

now just convert them to rectangular coords.

x = r cos @ y = r sin @
 

FAQ: Motion of a Particle in x-y Plane: Calculations

What is the basic equation used to calculate the motion of a particle in the x-y plane?

The basic equation used to calculate the motion of a particle in the x-y plane is the kinematic equation, which states that the position of the particle at any given time (x or y) is equal to its initial position plus its initial velocity multiplied by time, plus half of the acceleration multiplied by the square of time.

What is the difference between displacement and distance when calculating the motion of a particle in the x-y plane?

Displacement refers to the change in position of the particle from its initial position to its final position, while distance is the total length traveled by the particle. In other words, displacement takes into account the direction of motion while distance does not.

How do you calculate the velocity and acceleration of a particle in the x-y plane?

The velocity of a particle in the x-y plane can be calculated by taking the derivative of its position equation with respect to time. Similarly, the acceleration can be calculated by taking the derivative of the velocity equation with respect to time.

What is the significance of the slope of a position vs. time graph in the x-y plane?

The slope of a position vs. time graph in the x-y plane represents the velocity of the particle. A positive slope indicates a positive velocity, while a negative slope indicates a negative velocity. A zero slope represents a stationary particle.

How do you determine the direction of motion of a particle in the x-y plane?

The direction of motion of a particle in the x-y plane can be determined by analyzing its velocity and acceleration vectors. If both vectors have the same direction, the particle is moving in a straight line in that direction. If the vectors have different directions, the particle is moving in a curved path.

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