28 May 2009

classical physics jeopardy!

Classical Physics Jeopardy!!

Rules:
  • There are three teams of up to 8 students, as equal as possible. The teacher may weight teams so that the strongest students are in smaller groups. (If there are more than 24 students, there should be more teams so that there are never more than 8 in a group.)
  • The potpourri category does not have a 100-point question so that each team gets to choose the same number of questions. This works with 3 or 4 teams (and there shouldn't have to be more than 4 teams!)
  • A little different from "traditional" Jeopardy -- answers are not in the form of a question.
  • Each team elects a spokesperson at the beginning of the game. Only this person's answers count as the team's answer. A team loses 50 points every time the spokesperson does not confer with the group before answering, even if they were wrong! This is a group competition.
  • Each team in turn chooses a question and gets the first chance to answer it.
  • 100, 200, and 300-point questions: team has 30 seconds to conference before the spokesperson must answer or forfeit.
  • 400 and 500-point questions: team has 1 minute to conference before the spokesperson must answer or forfeit.
  • If the first team is incorrect, the next team in the sequence may answer for half points, and has half the conference time. If the second team is incorrect, this continues (further half points and half time) until all teams have had a chance.
  • Daily Doubles -- Team may wager points up to what they have or the question value (whichever is larger). If they are incorrect, the next team may answer for half the given point value (not a wager).
  • Final Jeopardy -- each team places a wager before the question is revealed. Each team has five minutes to solve the problem. Partial credit for each correct question: 0 correct = minus full wager, 1 correct = minus half the wager, 2 correct = plus half the wager, 3 correct = plus full wager.

Newton's Laws
  1. F = ma is the most common form of which of Newton's laws? (Second)
  2. A book pushes down on the table with 10 Newtons of force. With how much force does the table push back? (10 Newtons)
  3. (Daily Double) A large man and a small woman are standing on a bus that comes to a stop. The woman stumbles, and the man keeps his footing. Who has more inertia? (The woman, because she has less mass.)
  4. State Newton's Laws in sentence form. (1. An object in constant motion will remain in constant motion, and an object at rest will remain at rest, unless acted upon by an outside force. 2. A force acting upon a massive object will cause that object to accelerate. 3. For every force applied to an object, the object exerts an equal and opposite force.)
  5. A 1000-kg car is initially at rest. You push it with a constant force for 100 seconds, at which point it is traveling 5 m/s. What was your pushing force? (50 Newtons -- a = v/t = 5 m/s /100 s, f = ma = 1000 kg * 5/100 m/s/s.)
Vectors and Projectiles
  1. I walk one block north, then one block south. What is the magnitude and direction of the resultant vector? (Zero, which has no direction.)
  2. You throw a ball directly upwards, then catch it in your hand at the same height. It was in the air for a total of 8 seconds. At what time was the ball's velocity zero? (4 seconds after you threw it, at the point where it changed directions.)
  3. Does a projectile on Earth experience horizontal acceleration, vertical acceleration, both, or neither? If there is acceleration, what causes it? (Vertical acceleration only -- caused by gravity. Also OK: Both, since there may be horizontal drag forces.)
  4. Find the sum (magnitude and direction) of these vectors: 1 m/s up (0 degrees), 2 m/s to the right (90 degrees), and 3 m/s down (180 degrees). (Sqrt(8) m/s at 135 degrees.)
  5. A cannonball is shot at some angle on level ground. What equation should you use to find how long the cannonball is in the air, and why? Assume it is shot from ground level and neglect air resistance. (v_y(t) = 0 = -gt + v_oy -- solving for t tells you the time at which vertical velocity is zero, which is the top of the arc. Twice this is the total flight time.)

Energy and Electronics
  1. State the Work-Energy Theorem. (The work done on a system is equal to the total change in energy of the system.)
  2. What equation relates voltage, current, and resistance? (Ohm's Law, V=IR.)
  3. A 5-kg rock is held 10 m above the ground and dropped. How much kinetic energy does it have right before it hits the ground? Assume acceleration due to gravity is 10 m/s/s. (500 Joules -- KE = PE = mgh.)
  4. What is the total resistance when a 10-Ohm resistor is connected in parallel with two 5-Ohm resistors that are connected in series? (1/(1/10 Ohms + 1/(5+5) Ohms) = 5 Ohms.)
  5. (Daily Double) Describe how a generator in a hydroelectric dam produces an electric current. (The water turns a turbine, which turns a loop of wire in a magnetic field. This induces a current in the wire loop.)

Units
  1. What is the SI unit of acceleration? ( m/s/s )
  2. What is the SI unit of force, and what are its fundamental components? (Newton = kg*m/s^2)
  3. What is the SI unit of work, and what are its fundamental components? (Joule = N * m = kg*m^2/s^2)
  4. What is the SI unit of electric current, and what are its fundamental components? (Amp = coulomb/second)
  5. What is the difference between weight and mass? (Weight is a force, and mass is a fundamental quantity. Weight is measured in Newtons, and mass is measured in kilograms. An object can have different weights depending on the situation, but its mass does not change.)

Potpourri
  1. (Spare question) What is the gravitational acceleration at the surface of the earth, to one decimal place? (9.8 m/s/s)
  2. What is the name of the force that your chair is exerting on you? (The normal force.)
  3. How much force does a 1/10-kg apple exert while sitting stationary on Isaac's head? (1/10 kg * 10 m/s/s = 1 Newton.)
  4. What is the first step in the scientific process? (Create a hypothesis.)
  5. Name the four fundamental quantities and their SI units. (mass = kilograms, distance = meters, time = seconds, charge = coulombs)

Final Jeopardy
Category: Projectile motion

You are on the surface of Mars, where the gravitational acceleration is only 3.8 m/s/s. You get a running start and throw yourself into the air, with an initial velocity vector of 5 m/s at 30 degrees above horizontal. Neglect air resistance and presume the terrain is flat. 1. What is your velocity vector when you hit the ground again? 2. How long were you in the air? 3. How far did you jump?

1. 5 m/s at 30 degrees below horizontal (same as initial, but down).
2. 1.3 seconds
3. 5.6 meters