From f1af1fd1de76fb566fc99c59b76cb9accf1605dd Mon Sep 17 00:00:00 2001 From: Holden Rohrer Date: Thu, 14 May 2020 16:50:46 -0400 Subject: added ap-physics1-exam --- ap-physics1-exam/q1.txt | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 ap-physics1-exam/q1.txt (limited to 'ap-physics1-exam/q1.txt') diff --git a/ap-physics1-exam/q1.txt b/ap-physics1-exam/q1.txt new file mode 100644 index 0000000..b2b5c7c --- /dev/null +++ b/ap-physics1-exam/q1.txt @@ -0,0 +1,46 @@ +WY5V8181 +HR + +(a) + +Graph B is correct because the magnitude of acceleration is constant in +simple circular motion, so the magnitude of net force is proportional +and thus constant (F = ma). + +(b) + +The magnitude of tension on the string is greater than the centripetal +force on the sphere. Tension has two components, the opposite force to +gravity because the sphere is in equilibrium vertically, and the +centripetal force. The resultant of two nonzero forces is larger than +either component, so tension > centripetal force. + +(c) + +The inward acceleration needn't be as large for a very small tangential +speed to keep the sphere in constant circular motion. This means that +the centripetal force can be smaller. If the centripetal force can be +smaller but the vertical force of tension counteracting gravity is the +same, then the angle of the string and the pole is smaller. + +(d) + +This equation is consistent with part (c) because, for small values of +theta (string nearly vertical), tan(theta)*sin(theta) ~ 0, so v^2 ~ 0, +so v ~ 0 (small). + +(e) + +v^2 = gL*tan(theta)*sin(theta) +=> g = v^2 / (tan(theta) * sin(theta)). + +If v^2 were graphed on the y-axis of a graph and +(tan(theta) * sin(theta)) on the x-axis, the slope of the line of best +fit would give an experimental value of g. + +(f) + +As theta decreases, the distance of the sphere to the rod decreases. +The masses of all objects remains const, I = mr^2 for a point-like +object, and the distances from the pivot (and thus inertia) remain the +same for the rod and the platform. Therefore, as r -> 0, I -> 0. -- cgit