A particle leaves its initial position \(x_{0}\) at time \(t=0,\) moving in the positive \(x\) -direction with speed \(v_{0}\) but undergoing acceleration of magnitude \(a\) in the negative \(x\) -direction. Find expressions for (a) the time when it returns to \(x_{0}\) and (b) its speed when it passes that point.

Short Answer

Expert verified
The time when the particle returns to the initial position \(x_{0}\) is \(t = 2v_{0}/a\), and the speed at which it passes that point is \(v = 0\).

Step by step solution

01

Identify Relevant Concepts from Physics

To solve the problem, the equations of motion will be used, one of which states \(x = x_{0} + v_{0}t - 0.5at^2\). This equation comes from the basic definition of acceleration and describes the position of an object given its initial position \(x_{0}\), initial velocity \(v_{0}\), acceleration \(a\) and the time \(t\).
02

Setup and Solve the Equation for Time

The time when the particle returns to its original position means that \(x = x_{0}\). Substituting this information into the motion equation gives: \(x_{0} = x_{0} + v_{0}t - 0.5at^2\). We can simplify this to obtain the equation for the time when the particle returns to its original position \(t = 2v_{0}/a\).
03

Setup and Solve the Equation for Speed

Another equation of motion can give the speed (velocity) of an object given its initial velocity, acceleration and the time, which is \(v = v_{0} - at\). Substituting the time \(t = 2v_{0} / a\) obtained from last step into the speed equation gives: \(v = v_{0} - a(2v_{0}/a)\), simplifying this gives the speed when the particle returns to its original position \(v = 0\).

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