 PhysicsBowl 2011 (Part 2) Printer Friendly Version
26. During the New Moon phase of the lunar cycle, approximately what percent of the Moon’s surface receives light from the Sun?
27. The density of a solid cubic block is given as ρ = 0.750 g/cm3. This block is dropped into a large swimming pool filled with water. When equilibrium is established and all motion stops, which choice best describes the location of the block? The block is very small in comparison to the pool.

28. A person throws an object of mass M straight upward with an initial non-zero speed v. The object rises to a maximum height H above the launch point. The person now throws an object of mass M/2 straight upward with initial speed 2v. In terms of H, to what maximum height does the object of mass M/2 rise above the launch point? Ignore air resistance.
29. An electron moves with speed 1.00 x 103 m/s as it enters a region of space that has only a uniform magnetic field. The electron is accelerated because of this field with a constant magnitude of 8.00 x 105 m/s2 for the entire time of 1.00 x 10-3 s that it is in the field. With what speed would the electron exit the field? Ignore gravity.
30. Two cars travel to the right, each starting from rest, along a straight road. Car A has twice the acceleration of Car B. After traveling a distance d, Car A has speed v. When Car B has traveled the same distance d, what is its speed in terms of v?
31. Approximately how much energy is required to transform a 20.0 g cube of ice at a temperature of -10.0 ºC into liquid water at a temperature of 10.0 ºC
32. An ideal green pigment is mixed with an ideal red pigment. After mixing, which one of the following choices best represents the color of the pigment produced? 33. For the set-up shown of a candle and screen placed 30 cm apart, there are two locations at which a thin converging lens can be placed to produce a focused real image. One real image of the candle appears on the screen when the lens is located 12 cm from the candle. From this location, how does this lens now have to be moved in order to make the second real image of the candle appear on the screen? 34.  A wire lies in the plane of the page with conventional current I shown. At the instant shown, what is the direction of the magnetic force on the electron that is moving directly to the right toward the wire?

35. Mary rides her bicycle directed due South. She applies the brakes quickly bringing the bicycle to rest with the wheels rolling without slipping on the ground. Which one of the following choices best represents the direction of the angular acceleration of the bicycle’s front wheel while it is slowing to rest from Mary’s point of view? 36. For the inclined plane shown, a force of 150 N applied parallel to the incline’s surface is needed to pull the object of mass M = 10.0 kg along the entire length of the incline’s surface at a constant speed. What is the actual mechanical advantage (AMA) for this scenario? 37. Two blocks sit on a horizontal frictionless surface connected to an ideal spring. Initially everything is at rest and there is a string compressing the mass-spring system from equilibrium. At some time after the string is cut, the block of mass 2M reaches its maximum kinetic energy K. What maximum kinetic energy does the block of mass M attain in terms of K? 38. For the circuit shown, the four light bulbs have identical resistance, all wires have zero resistance, and the battery is assumed to be ideal with When the switch, S, in the circuit is closed, a wire of zero resistance is added into the circuit. Which of the light bulbs will be dimmer after the switch is closed?

39. An object with mass M moves due East on a frictionless horizontal surface with a speed of V. A second object of mass M/2 has a speed of 3V. The two objects collide and stick together. If the objects are moving due South after the collision, with what speed are they moving?
40. A 2.0 kg particle travels at a constant speed of 5.0 m/s along the line shown in the figure.What is the magnitude of the particle’s angular momentum calculated from the origin? All Division 01 students STOP HERE. Your last answer should be for #40. Numbers #41-#50 should remain blank for Division 01 students.
All Division 02 students continue to Questions 41 – 50. 41. For the figure shown, the variable resistance of the outer circuit, Router, is decreasing at a constant rate. While this is occurring, in which direction is the magnetic field associated with the outer circuit at the point P in the plane of the circuit and in which direction is the conventional current through the resistor Rinner in the smaller interior circuit? The two circuits lie on a flat table. 42. A parallel-plate capacitor of capacitance C has an insulating dielectric material of constant filling the entire region between its plates. This capacitor now is connected to a battery of voltage V and is fully charged before the battery is disconnected. The capacitor stores energy U. Using insulating gloves, a person now removes the dielectric from the capacitor. After equilibrium is established following the removal of the dielectric, which one of the following choices best represents the energy stored by the capacitor in terms of U?
43. A standing wave is created in an air-filled tube open at both ends when a tuning fork of frequency 552 Hz is placed near one of the open ends. A tuning fork of frequency 644 Hz produces the next highest harmonic for this tube. What is the length of the open tube? Assume room temperature.
44. One mole of a monatomic ideal gas undergoes an isobaric expansion. In the process, the temperature of the gas increases from 300 K to 500 K. Which one of the following choices best represents the amount of work done by the gas on the surroundings?
45. An object is placed in front of a thin converging lens resulting in a focused image forming on a screen. If the bottom half of the lens were covered with black paper, what happens to the image on the screen? 46. A hollow conducting sphere in static equilibrium is isolated in deep space with a net excess charge +Q on it. What is the electric potential (assuming at the position labeled P shown in the interior of the figure? The sphere has radius r = 3a and the point of interest is at a location r = 2a from the center of the sphere at an angle of 60° with respect to the +x-axis. 47. A simple pendulum of length L has a point mass M released from rest from the horizontal position shown. In the absence of air resistance and friction, the mass swings through the arc of a circle. Let T represent the magnitude of the force from the string on the mass (tension), G represent the magnitude of the gravitational force acting on the mass by the earth, and F represent the magnitude of the net force acting on the mass. Which one of the following choices describes the relationship among these forces when the mass swings at the bottom of the arc (point P)?
48. An electromagnetic wave has a magnetic field given by the expression (in Cartesian coordinates): At time = 0 and position x = y = z = 0, what is the direction of the electric field associated with this wave? 49. An inverted “V” in static equilibrium is made from two uniform beams each of mass M = 12 kg. Each beam of the “V” has the same length and makes an angle of 30° with the vertical as shown in the diagram. Which one of the following choices best represents the magnitude of the static friction force acting on the left leg of the “V” from the level ground? The coefficient of static friction between each beam and the ground is µs = 0.76.
50. A person sets a one-meter long stick so that it makes a 30° angle with the x-axis. An observer in a space ship moving along the x-axis measures the angle of the stick to be 60° with the x-axis. With what speed is the space ship moving in terms of the speed of light, c?

All Division 02 students STOP HERE. Your last answer should be for #50. Related Documents