🎡AP Physics 1
🎡AP Physics 1
FRQ 1 – Mathematical Routines
Unit 1: Kinematics
Practice FRQ 1 of 201/20
1. A student stands on a long, straight moving walkway in an airport. The walkway moves in the +x-direction at a constant speed of 1.50 m/s relative to the ground. At time t = 0, a toy cart moves on the walkway and is launched from point P on the walkway, as shown in Figure 1. The student and a second observer on the ground both observe the cart's motion.
Figure 1. Top view of the moving walkway and launch velocity. The x–y axes represent the ground reference frame; the cart is launched from point P with speed 2.50 m/s at 30.0° above +x as measured in the walkway frame, while the walkway itself moves at 1.50 m/s in +x relative to the ground.
Figure 2. Axes for graphing the cart’s ground-frame x-position as a function of time from 0 to 3.00 s, with x = 0 at point P at t = 0.
A.
i. On the axes shown in Figure 2, sketch a graph of the cart's x-position as a function of time t from t = 0 to t = 3.00 s as measured by the ground observer. Let at point P at .
ii. Derive an expression for the x-component and y-component of the cart's velocity as measured in the ground frame in terms of the given values 2.50 m/s, 30.0°, and 1.50 m/s. Begin your derivation by writing an equation that relates velocity measurements in different inertial reference frames.
iii. Derive an expression for the magnitude of the cart's displacement from P to its position at as measured by the ground observer. Express your answer in terms of the given values and physical constants, as appropriate. Begin your derivation by writing equations for the cart's x- and y-displacements in the ground frame.
The student on the walkway claims that because the cart moves with constant velocity in the walkway frame, the cart must also have constant velocity in the ground frame. Another student claims that the cart's average acceleration from t = 0 to t = 3.00 s is zero in both frames, but the cart's average velocity over that time interval is different in the two frames.
B. Indicate whether the first student's claim is correct.
______ Correct
______ Incorrect
Justify your response by explicitly referencing the two inertial reference frames and how the measured velocities are related. Then, determine whether the second student's claim about average acceleration and average velocity is correct.
______ Correct
______ Incorrect
Justify your response.
______ Correct
______ Incorrect
Justify your response by explicitly referencing the two inertial reference frames and how the measured velocities are related. Then, determine whether the second student's claim about average acceleration and average velocity is correct.
______ Correct
______ Incorrect
Justify your response.
