🎡AP Physics 1
1. Two students observe a small puck moving on a nearly frictionless horizontal air table. Student A stands on the ground and uses reference frame A. Student B stands on a walkway that moves at a constant velocity relative to the ground and uses reference frame B. A coordinate system is defined with +x to the east and +y to the north, as shown in Figure 1.
Figure 1. Top view of the air-table motion and the two inertial reference frames (A: ground, B: moving walkway).
Figure 2. Axes for plotting puck x-position in reference frame A, x_A versus time t.
On the axes shown in Figure 2, sketch a graph of the puck’s x-position as a function of time in reference frame A from until .
Derive an expression for the magnitude of the puck’s displacement from to as measured in reference frame A. Express your answer in terms of , , and . Begin your derivation by writing a fundamental physics principle or an equation from the reference information.
Derive an expression for the average velocity vector of the puck from to in reference frame A. Express your answer as perpendicular components in the form in terms of and . Begin your derivation by writing a fundamental physics principle or an equation from the reference information.
Indicate whether the magnitude of the puck’s velocity measured in reference frame B is greater than, less than, or equal to the magnitude of the puck’s velocity measured in reference frame A. Student B’s walkway moves east at a constant velocity relative to the ground. Student B measures the puck’s motion in reference frame B, which is an inertial reference frame.
Greater than
Less than
Equal to
Justify your response by describing how velocities transform between inertial reference frames and applying it to this situation.
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