AP Exam Review Notes

AP Exam Review #4

• Energy
  • Energy is the ability to cause change (lash, speed, compression, etc.).
  • The slope of Force ($\text{F}$) and displacement ($\text{x}$) graph is the spring constant.
  • The area under the Force ($\text{F}$) and displacement ($\text{x}$) graph is work.
  • Important to remember the shapes of common graphs ($x^2$, $\sqrt{x}$, etc.).
• System Interactions
  • Any interactions inside a system don't change overall energy.
  • Interactions outside a system can change energy, like adding a gravity force or friction force.
• Work
  • Work is a force parallel to displacement that causes a change in energy.
  • Negative work is done by friction.
• Lot Charts
  • Lot charts are simpler than they appear.

Review Session 3

• Yo-yo Tension
  • There's no normal force in suspension.
  • How to find the tension of a Yo-yo at the top of its path:
    • $\sum F = ma$
    • $F_{net} = ma$
    • $F_T + mg = \frac{mv^2}{r}$
    • If tension is up: $F_T + mg = m\frac{v^2}{r}$

#3

• $F<em>g = G \frac{m</em>1 m_2}{r^2} = G \frac{87 \cdot 10}{r^2}$
• Even when released from rest, an object is always accelerating thanks to the force of gravity ($F_g$).