The correct answer is (C). Refrigerators and freezers operate in a reversed direction from a heat engine. Instead of using a hot source to produce work, work is done on a warm source and heat is removed, producing the cooling effect.

The correct answer is (A). Gravity has nothing to do with heat transfer. Both objects will reach the same temperature when they have reached equilibrium.

The correct answer is (C). The two surfaces (hockey puck and ice) are essentially frictionless. The movement of the train around a curve has no effect on the puck, which continues to move in a straight line. The goal does move around the curve with the train. This moves the net to the left, while the puck travels in a straight line.

Using Big Five #2 (with v0 = 0), we get (delta)s = at2 = (4 m/s2)(6 s)2 = 72 m.

The correct answer is (D). According to Newton's first law, an object in motion remains in motion and an object at rest remains at rest unless a net force acts on the object. The ball is in free fall. Even though it is accelerating on the y axis (up and down), nothing is affecting the ball on the x axis (horizontal)

The correct answer is (C). The voltage of the battery is equal to electrical potential energy, and the kinetic energy is .5mv2. Setting the two equal to each other, .5mv2 = (1.5V)(q). Solving the equation yields 7.3e5m/s, which is the velocity of the electron just as it reaches the positive plate of the battery.

Since the magnetic force is always perpendicular to the object's velocity, it does zero work on any charged particle. Zero work means zero change in kinetic energy (a direct consequence of the work-energy theorem), so the speed remains the same. Remember: The magnetic force can only change the direction of a charged particle's velocity, not its speed.

The correct answer is (B). The carbon atom changes into a nitrogen atom. This conversion can only occur if a neutron emits a beta particle as it changes into a proton.

The correct answer is (A). An unbalanced torque causes motion to occur. The child can push the door open because she applies the unbalanced torque.

The frequency determines the pitch of a sound, and the amplitude determines the intensity (or loudness). Pitch and loudness are independent. (A sound can be soft and low pitched, soft and high pitched, loud and low pitched, or loud and high pitched; there's no connection.)

To balance the mass number (the superscripts), we must have 196 + 1 = 197 + A, so A = 0. To balance the charge (the subscripts), we need 78 + 0 = 78 + Z, so Z = 0. The only particle listed that has zero mass number and zero charge is a gamma-ray photon, .

The correct answer is (B). The temperature of a gas is directly related to the rate at which gas particles strike the sides of the container in which the gas is contained. The measure of the number of times gas particles strike the sides of the container is pressure. Charles Law shows the direct relationship between the two. When the temperature increases, the pressure increases. This means the velocity of the gas particles increases, too.

The correct answer is (E). Each bright spot is a point at which waves constructively interfere. The waves combine at whole number wavelength intervals. This means at 1, 2, 3, etc., wavelengths.The third maxima is where a three-wave difference in the path length occurs.

Use Big Five #5 with v0 = 0 (calling down the positive direction).

The correct answer is (D). The inertia of the dishes (Newton's first law) causes them to remain at rest. The fast rate at which the magician pulls the tablecloth from under the dishes keeps the static friction from changing to kinetic friction.

The correct answer is (D). Any time a net or unbalanced force is applied to an object, the object is accelerated.

The correct answer is (C). The problem can be solved as a combination work-energy theorem problem. KE = Work is restated as 1/2 mv2 = (Ff)(s)(cosθ). The Ff is found by using the equation for frictional force, Ff = μN. Put it all together and solve

The correct answer is (D). The wavelength is found by dividing the frequency of the waves into the velocity of the waves λ = v/f.

The correct answer is (E). The sum of the individual masses of the parts of a nucleus is less than their mass when they are bound into the nucleus-producing mass defect. The mass from the mass defect is converted into the energy that holds the nucleus together and is released in fission. Fusion also produces energy when individual nuclei are forced to combine (fusion) and form new elements in a process that produces energy.

The correct answer is (A). Since , the person will be weightless at the center of the earth because r = 0, and all the mass of the earth is attracting the person from outside the center.

The correct answer is (E). Of the choices listed, the only electromagnetic radiation that carries more energy than the blue light is ultraviolet.

The correct answer is (B). If an object is placed inside the focal point of a concave mirror, so that s < t. the resulting image is virtual (that is, the image point is on the opposite side of the mirror from the object), erect, and larger than the object.

The correct answer is (E). When the pendulum is displaced, the potential energy the pendulum gains is equal to the height above the zero point to which the pendulum is raised. When the pendulum is released, all the potential energy at its displaced position is converted into kinetic energy. Thus, a smaller displacement gives the pendulum less potential energy, which in turn yields less kinetic energy when the bob moves through the zero point.

Newton's second law is Fnet = ma, so if we know Fnet and m, we can calculate the acceleration, a.

The correct answer is (B). When the object leaves the hand of the person who throws it out of the vehicle, the object is in free fall. The acceleration of any object in free fall is a constant 9.8 m/s2, therefore the acceleration does not change. Since there is acceleration, however, the velocity will change.

The correct answer is (E). An object that is not being accelerated cannot have any unbalanced forces acting upon it. The car is moving at a constant velocity, which means there are no forces exerted on the car anywhere.

The correct answer is (E). The battery that provides the force to push electrons through the circuit causes the electrons to jump from atom to atom, a process that causes the current to flow. The process is similar to water flowing in a hose. Water enters one end of the hose and leaves the other end, but they are not the same water molecules.

The correct answer is (A). The pressure he feels is equal to force per unit area. His partner's heel is a tiny area, which bears most of her weight. This gives a large local force at the small end of her heel.

The correct answer is (D). While the light ray is moving through an optically denser material, its velocity decreases.

The correct answer is (E). Work can be either a positive quantity or a negative quantity. When a force is applied in one direction and the displacement is in the opposite direction, the work equation becomes F·s·csine 180 degrees The cosine of 180 degrees is -1, therefore any work done under those conditions is negative work. W = -F·S = -(1000N)(10 m) = -10,000 J

The correct answer is (E). Two different objects that are in thermal equilibrium must be at the same temperature.

Use the equation Q = mc ∆T.

In order for total internal reflection to occur, the beam must be incident in the medium with the higher index of refraction and strike the interface at an angle of incidence greater than the critical angle. Since v1 < v2, the refractive index of Medium 1, n1 = c/v1, must be greater than the index of Medium 2 (n2 = c/v2), and the critical angle is θcrit = sin−1 (n2/n1) = sin−1 (v1/v2).

First we determine the time required for the ball to reach the top of its parabolic trajectory (which is the time required for the vertical velocity to drop to zero).

The correct answer is (E). Sound waves are propagated in a manner that is parallel to their direction of movement. They are composed of a series of compressions and rarefactions.

The correct answer is (E). All of the choices are correct. Clocks on the spaceship move more slowly, the length of the spaceship would be contracted, the relativistic mass of the spaceship is greater than the rest mass, and the velocity of light is constant for everyone.

The correct answer is (C). The sample has three half-lives occurring in one hour.. Next, we have . The original counts are multiplied by the amount ofthe sample remaining: .

The correct answer is (D). The relativistic equation is . In the eyes of an outside observer, the ship undergoes a contraction.

Because the image is virtual, we must write the image distance, si, as a negative quantity: si = -20 cm. Now, with so = 60 cm, the mirror equation gives

The correct answer is (C). When the ice cube enters the boiling water, the heat in the water immediately begins to change the phase of the ice to water. Consequently, the higher energy phase change (boiling) stops until the lower energy phase change (melting) is complete.