Problems

#	Title	Difficulty	Solved	Accept.
1	Biaxial Plate PendulumHard	Hard	5	38.5%
2	Springy Hoop PendulumMed.	Med.	8	28.6%
3	Squirt Gun EnergyMed.	Med.	8	72.7%
4	Work in a Moving FrameEasy	Easy	25	37.9%
5	Trailing SledHard	Hard	6	54.5%
6	Piezometer Elevation DropMed.	Med.	5	62.5%
7	Sag and LiftMed.	Med.	2	20.0%
8	Spring Lift-OffMed.	Med.	7	77.8%
9	Centrifugal BuoyancyMed.	Med.	4	100.0%
10	Sweeping Satellite in Dust CloudMed.	Med.	3	100.0%
11	Ambiguous InelasticityEasy	Easy	11	73.3%
12	Rolling on a Moving RampMed.	Med.	4	80.0%
13	Energy of a Robotic ArmMed.	Med.	4	66.7%
14	Center of Mass ShiftMed.	Med.	2	50.0%
15	Reinforced TripodMed.	Med.	1	—
16	Rolling Cylinder on a SpringMed.	Med.	5	100.0%
17	Center of Percussion of a DumbbellMed.	Med.	3	60.0%
18	Elevator OscillatorsMed.	Med.	5	83.3%
19	Double Conical PendulumMed.	Med.	3	60.0%
20	Rolling to Slipping TransitionMed.	Med.	2	66.7%
21	Oscillator in a Shrinking CavityMed.	Med.	3	100.0%
22	Force on a Shifting AxisMed.	Med.	3	100.0%
23	Adiabatic Mass LossMed.	Med.	5	100.0%
24	Compound-Wheel CascadeMed.	Med.	0	—
25	The Hexagonal Space Station IMed.	Med.	8	29.3%
26	The Hexagonal Space Station IIHard	Hard	6	50.0%
27	The Hexagonal Space Station IIIHard	Hard	2	100.0%
28	Coincident FrequenciesMed.	Med.	3	37.5%
29	3D Ring FrictionMed.	Med.	4	66.7%
30	Sequential Frictional StoppingMed.	Med.	4	57.1%
31	Coupled Friction on SledEasy	Easy	9	60.0%
32	Momentum Flux TensionMed.	Med.	3	75.0%
33	Dust Drag on HemispheresMed.	Med.	2	100.0%
34	Hidden Mass Spring PendulumMed.	Med.	2	40.0%
35	Density Error PropagationEasy	Easy	6	66.7%
36	Sandwiched Slipping BlocksMed.	Med.	3	42.9%
37	The PH-SL0 Droid IMed.	Med.	4	40.0%
38	The PH-SL0 Droid IIHard	Hard	2	50.0%
39	The PH-SL0 Droid IIIHard	Hard	2	100.0%
40	Restricted Collision StatesMed.	Med.	5	83.3%
41	Turntable String TensionMed.	Med.	5	62.5%
42	Randomly Sampled OrbitMed.	Med.	3	75.0%
43	Free Rod CollisionMed.	Med.	4	33.3%
44	Heavy Hoop PendulumMed.	Med.	6	66.7%
45	Frame-Dependent Launch EnergyEasy	Easy	7	87.5%
46	Slipping Stack AccelerationMed.	Med.	4	80.0%
47	Friction Over a Curved PathMed.	Med.	5	100.0%
48	Impulsive FrictionMed.	Med.	5	100.0%
49	Tapered Capillary TubeMed.	Med.	8	100.0%
50	Turntable Doppler SpectrumMed.	Med.	5	62.5%
51	Near-Side Tidal WeightMed.	Med.	2	33.3%
52	Bouncing Particle and Massive BlockHard	Hard	4	66.7%
53	Constant Power ScalingEasy	Easy	7	46.7%
54	Cradled DescentHard	Hard	1	—
55	The Hidden HorizontalEasy	Easy	0	0.0%
56	Twin CavitiesMed.	Med.	0	—
57	Pegged PendulumMed.	Med.	0	—
58	Critical Speed LimitMed.	Med.	1	33.3%
59	Cascading Slip ThresholdsHard	Hard	1	—
60	Threshold to TumbleMed.	Med.	0	—
61	Compounded Spring StiffnessMed.	Med.	0	—
62	Quarter-Period RendezvousEasy	Easy	1	—
63	Pumping the PendulumMed.	Med.	0	—
64	Maximum LiftMed.	Med.	0	—
65	After LiftoffEasy	Easy	4	80.0%
66	Slipping ShellMed.	Med.	0	—
67	Calibrating by PeriodMed.	Med.	1	50.0%
68	Cascading DisadvantageMed.	Med.	0	—
69	Layered WindMed.	Med.	1	50.0%
70	Equal-Time Dead ZoneMed.	Med.	0	—
71	Hidden GaussianEasy	Easy	1	—
72	Tilted Free FallMed.	Med.	1	—
73	Coalescence CeilingMed.	Med.	0	—
74	Free Ballistic CaptureMed.	Med.	0	—
75	Effective AnchorMed.	Med.	0	—
76	Lifting a Submerged ConeMed.	Med.	0	—
77	The Yielding WedgeMed.	Med.	1	50.0%
78	Decay InvariantsMed.	Med.	1	—
79	Pumping the SwingHard	Hard	2	66.7%
80	Compound AccelerationMed.	Med.	1	—
81	Triangular JointsMed.	Med.	0	—
82	Hexagonal PivotMed.	Med.	0	—
83	Lunar-Gravity ParabolaEasy	Easy	1	—
84	Rigid Rod Conical PendulumMed.	Med.	0	—
85	Successive ReboundMed.	Med.	0	—
86	Reluctant AnvilHard	Hard	1	—
87	Subterranean PerihelionMed.	Med.	0	—
88	Apsides After ImpulseMed.	Med.	1	—
89	Torsion Disk ReboundMed.	Med.	0	—
90	Threshold of MotionEasy	Easy	0	—
91	Whirling Bowstring StabilityMed.	Med.	0	—
92	Inverted CascadeMed.	Med.	0	—
93	Floater's TollMed.	Med.	0	—
94	Pendulum Sweet SpotMed.	Med.	0	—
95	Background-Limited CountingMed.	Med.	0	—
96	Capped RangeMed.	Med.	1	—
97	Climbing in PlaceMed.	Med.	0	—
98	Crosswise Frictional HeatingMed.	Med.	0	—
99	Trapped Rotational EnergyEasy	Easy	1	—
100	Asymptotic CruiseMed.	Med.	0	—
101	Pseudogravity DecayEasy	Easy	0	—
102	Convection on a ScaleMed.	Med.	0	—
103	Asymptotic StoppingMed.	Med.	1	—
104	Coriolis CancellationHard	Hard	0	—
105	Diving Board FailureMed.	Med.	0	—
106	Keplerian Catch-UpMed.	Med.	0	—
107	Comparing Mint BatchesEasy	Easy	0	—
108	Common Rim SpeedEasy	Easy	0	—
109	Decoupled DescentEasy	Easy	1	50.0%
110	Traction-Limited LapMed.	Med.	1	—
111	Galilean Energy AccountingMed.	Med.	0	—
112	Power-Limited MicroswimmerEasy	Easy	2	50.0%
113	Synodic TerminatorMed.	Med.	0	—
114	Climbing the WellMed.	Med.	2	100.0%
115	Orbital ShrapnelHard	Hard	1	—
116	Crossed Spring EquilibriumMed.	Med.	0	—
117	Rolling Oscillator on a Slippable PlatformMed.	Med.	0	—
118	Fountain Apparent WeightMed.	Med.	2	100.0%
119	Closing the LoopHard	Hard	3	100.0%
120	Where the Heat GoesMed.	Med.	1	25.0%
121	Heavy-Planet DrillMed.	Med.	0	—
122	Linear Drag StopEasy	Easy	2	100.0%
123	Spinning ManifoldMed.	Med.	2	66.7%
124	Centrifugal FailureMed.	Med.	1	—
125	After the ReleaseEasy	Easy	2	100.0%
126	Fluctuation-Induced BoostHard	Hard	0	—