AP Physics C: Mechanics 2007 Free Response Questions

Summary The question is a basic force problem about a block sliding across a surface with some frictional force. The whole thing is symbolic and algebraic, with some graphs at the end of the problem

Concepts Used Force Method and Algebra, as well as graph knowledge

Issues The graph can be tricky, if you don’t use kinematics to analyze the motion of the block. Part E is a little strange, but if you set normal force equal to zero, it can be solved pretty easily.

Summary This problem was a circular motion problem, involving the movement of some satellite around the planet Mars. You were asked to solve for various things like the mass of Mars and the energy of the system.

Concepts Used Force Method, Circular Motion, Energy, Gravitational Energy and Forces

Issues Knowledge of what equations to use was key to solving this problem, as it can take awhile cycling through every equation about circles.

Summary This problem was the “experiment” problem on the 2007 exam. It involved the conservation of energy as a spring was stretched and the glider attached sped up. After this, again graphing was a useful skill. Then the track was tilted, and conservation of energy had to be applied yet again.

Concepts Used Energy of a spring, kinetic energy, and potential energy

Issues Things can get a little complicated when you have to tilt the track, as then potential energy due to gravity plays an effect. But as always, with no outside forces conservation of mechanical energy holds true.