161Exams

PHYS 161 Exams
The handout at right provides guidance on grading yourself after you finish your test.	Self-grading Tips
Partial List of Topics Covered Anything in the book or lectures/labs is also fair game	Test	Solution	Comment
Chapters 1-4 Sig figs & math with sig figs Prefixes & Notations · Scientific versus engineering · Be able to go from power of 10 to prefix · Be able to go from prefix to power of 10 · WATCH OUT! Use either prefix or power of 10 BUT NOT BOTH!!! Vectors · Ordinal directions (N of W versus W of N) · Dealing with angles to the vertical versus angles to the horizontal · Addition (graphical or with SOH CAH TOA) · Cross & dot products · Creating unit vectors · Angle between two vectors · Angle between vector and an axis 1D motion graphs · Use problem statement to create a graph · Interpret graphs · Distinctions between an xt-plot versus a vt-plot versus an at-plot 1D, 2D & 3D motion · Standard projectiles (a_x=0) · Projectiles with non-zero a_x · Tricky word problems requiring derivatives or integrals. Remember: sometimes plugging in zero for a limit gives non-zero result! · Separation of variables · Relative motion	161sp24t1a	161sp24t1aSoln
	161sp23t1a	161sp23t1aSoln
	161sp22t1b	161sp22t1bSoln
	161sp22t1d	161sp22t1dSoln





Chapters 5-8 Excel or other computation Newton’s Laws · Frictionless force problems (often multi-block) · Friction force problems (often multi-block) · Circular motion force problems · Tricky concept questions Work-energy theorem (Ch 7 methods) Work done by non-constant force using integral Determine force from potential energy Determine potential energy from force · Remember: sometimes plugging in zero for a limit gives non-zero result! Energy problems (Ch 8 methods) Know these tricks: · Determining height of circular arc · Determine height on incline · For two blocks use two GPE reference levels · Use FBD to determine n & f so you can get W_friction · Often useful to do circular motion FBD for energy problems with circular tracks or loops · If spring is changing length in problem, we typically use energy (because spring force & acceleration are NOT constant).. Do NOT use constant acceleration kinematics if spring length is changing in problem! · If spring at fixed length for entire problem, we often can use F_spring=kx in an FBD · Use period, speed, &/or omega interchangeably for circular motion Kinematics relates to force using F=ma Instantaneous power is force dot velocity Average power is change in energy over change in time	161sp24t2a	161sp24t2aSoln
	161sp23t2a	161sp23t2aSoln
	161sp22t2a	161sp22t2aSoln
	161sp22t2c	161sp22t2cSoln




Chapters 9-12 Momentum and Impulse · 1D elastic · 1D or 2D inelastic · Explosions Center of Mass & Moment of Inertia · If calc required, expect a 1D problem · If calc NOT req’d, could be any dimensionality, could have holes, could require parallel axis · Perpendicular axis might be extra credit Rotational Kinematics · Constant angular accel · Non-constant angular accel · Plots · Know a, a_c, a_tan & a_total Relating Rotational & Translational Motion Torque & Energy Methods for: · Rolling Motion (without slipping) · Blocks with Massive Pulleys · Swinging Motion* *WATCH OUT! In most swinging motion problems you CANNOT use constant acceleration kinematics (while most rolling or blocks w/ pulley you CAN). Angular Momentum · Rotating object changes shape (e.g. neutron star, figure skater brings arms in). · Rotating object impacts rotating object (e.g. drop spinning disk on spinning turntable) · Collision in space without pivot: Usually both angular and linear momentum conserve. After collision rotates about center of mass. Often need parallel axis theorem to get moment of inertia. · Collision with pivot: Usually only angular momentum is conserved. After collision rotates about pivot. · For points masses moving in straight line use m v r_perp · For points masses attached to something spinning use I_pointmass = m x^2 · Don’t forget: angular momentum could be + or -!!! Which conservation laws apply? Static Equilibrium Stress & strain (1D Young’s modulus)	161sp23t3a	161sp23t3aSoln
	161sp22t3a	161sp22t3aSoln
	161sp22t3c	161sp22t3cSoln





Final exam is cumulative No practice tests provided Questions on the final from chapters 13 & 14 are very similar to homework questions from the problem list. I might put 2-3 concept questions and/or up to 2 problems from Chapter 13 & 14. Expect the remaining questions to a mix of concept questions and computational questions from everything else covered all semester. The calculations in final exam questions tend to be shorter than mid-terms. I try to shoot for approximately 25-30% of the test being relatively short conceptual questions but that is not always true. Ch 13—Universal gravitation · Circular orbit do FBD &/or KE & GPE · Conservation of energy (Escape velocity, release four point masses from rest, etc) · Place point masses on grid. Get net force on one of the masses. Remember that you must add force VECTORS not force MAGNITUDES. · Place point masses on a grid. Get gravitational potential energy. Ch 14—Fluids & Pressure · Buoyant force · Static pressure versus depth (U-tubes or force on a dam) · Ideal fluid flow problems using continuity equation &/or Bernoulli equation (e.g. siphon or hole in a can) · Sometimes throw in a 1 pointer from all the weird demos...not worth stressing over.