Physics Exam

[Yonah Ziemba]

Hi Everyone,

I hope the exam went OK for you....   The Physics Department said that our grades will be posted on Blackboard before tomorrow night. (They sometimes also post it on the bulletin board outside of Meyer 424). They said that Prof. Hogg also posts the  answer key online. (Now only the exam questions are posted as a link on schedule on  the syllabus webpage.)

They will not be giving us a breakdown of which questions we got right and which wrong. But if you want to see for yourself, you can pick up your answer sheet from Meyer 424 after the grades are posted and compare it to the answer key.

Many students felt that Q25 was not worded clearly. (See the question below). If you feel that way too, I think we should let Professor Hogg know and he might drop it.

 (Personally, I didn't want to complain so I phrased my email as a question, What did you really mean?...   "Now imagine" that each one was opposite to it's actual direction or  imagine they were opposite to each other?)

25.— [from Equilibrium of a Particle lab] Imagine that there are three forces A⃗, B⃗ and C⃗ acting on a particle such that the particle is in equilibrium.  Now imagine that forces B⃗ and C⃗ point in opposite directions. What is true of the force magnitudes?

 A:|A⃗|2 =|B⃗|2+|C⃗|2 B:|A⃗|2 =|B⃗|2+|C⃗|2−|B⃗||C⃗|cosθ C: |A⃗| = 0 and |B⃗| = |C⃗| D: All forces must have zero magnitude.

E: None of the above.

Good Luck!