The correct answer is (C). Gases provide electron sources that can be excited by the photons of light that strike them.

The correct answer is (A). Both disks move the same linear distance in the same time period. The smaller disk must make more revolutions to have the same tangential velocity as the large wheel. Since the number of revolutions for the small disk is larger, it also has a large angular acceleration.

Neither the velocity nor the acceleration is constant because the direction of each of these vectors is always changing as the object moves along its circular path. And the net force on the object is not zero because a centripetal force must be acting to provide the necessary centripetal acceleration to maintain the object's circular motion.

The correct answer is (D). The electric field between two parallel plates is constant throughout. The value of the field is defined as E = F/q where E is the electric field, F is force, and q is charge.

The correct answer is (C). Sound waves are compressional waves; thus they need a medium through which they can move. A vacuum does not provide a way for the compressions to move along.

The correct answer is (B). The radius of the curved path the electron follows in the magnetic field is r=mv/Bq. Both particles are electrons, which have the same mass, and the force exerted by the magnetic field remains the same, so the only difference is the velocity. The ratio of the velocity of the fast electron compared to the slow electron is 4:1.The fast electron has a radius 4 times larger than the slow electron.

The correct answer is (C). The problem may be solved in several ways. Perhaps the best solution is a little thought. E.g., the potential energy and the kinetic energy are equal to each other when the object has fallen half the distance to the ground, or 10 m. We now treat it as a free fall problem by restating the situation a little. What is the velocity of an object that starts from rest and free falls a distance of 10 m? The solution is found by

Fiber optic cables transmit light using total internal reflection. A, B, C, and D do not apply here.

Since the box (mass m) falls through a vertical distance of h, its gravitational potential energy decreases by mgh. The length of the ramp is irrelevant here.

The correct answer is (C). The velocity of the ball in its pathway is calculated with the centripetal force equation, , which is rearranged to

The correct answer is (C). The closer a satellite orbits the earth, the faster its period of rotation. The farther a satellite orbits from the earth, the longer its period of rotation.

The correct answer is (B). The satellite travels at essentially the same velocity in its orbit, although its speed does increase at its closest approach to the earth. The distance from the satellite to the earth also changes while the satellite orbits the earth. The closer approach to the earth decreases the radius of the orbit, which in turn causes an increase in the centripetal acceleration.

The correct answer is (A). The numerical value is the magnitude of the vector. The one with the largest numerical value is the longest vector.

Since we know g = 10 m/s2 on the earth, the value of g on the moon must be (10) = m/s2. So, if an object weighs 20 N on the moon, its mass must be

The correct answer is (E). The displacement of the motorcycle rider is found with .

The correct answer is (C). The coefficient of friction remains the same so the frictional force doubles, but the net force also doubles. Thus the crate is brought to a stop in the same distance.

The net force that the object feels on the inclined plane is mg sinθ, the component of the gravitational force that is parallel to the ramp. Since sin θ = (5 m)/(20 m) = 1/4, we have Fnet = (2 kg)(10 N/kg)() = 5 N.

The correct answer is (A). The period of a wave is the inverse of the frequency f = 1/T.

We use the equation q = mc(delta)T. Since both the aluminum block and the iron block absorb the same amount of heat, we have mAlcAl(delta)TAl = mFecFe(delta)TFe, where Al  denotes aluminum and Fe  denotes iron. Now, because mAl = 2mFe and cAl = 2cFe, we have

A is the first law of thermodynamics. C and E are true, but they are not equivalent to the second law of thermodynamics. B is false, but if it read, The efficiency of a heat engine can never be equal to 100 percent,  then it would be equivalent to the Second Law. D is one of the several equivalent forms of the second law of thermodynamics.

The correct answer is (E). The hot gas, which is in contact with the cold gas, will lose heat to the cold gas. The transfer of heat is always from the hot object to the cold object, unless work is done on the system.

The correct answer is (A). To find the capacitance for a group of capacitors in parallel with each other you add their capacitances together to find their sum. 10μf +15μf + 35μf = 60μf.

The correct answer is (B). The velocity of the pile driver at the time it first contacts the head of the nail is . Since, by conservation of energy, . V is also the original velocity as the nail is driven into the wood for a distance of .0245m. Stating the equations:

All excess electric charge on a conductor resides on the outer surface.

The correct answer is (A). In this problem the object has both horizontal and vertical motion. The original velocity of the object can be of large magnitude on either the x axis or the y axis. It is absolutely true, however, that the object can only travel along the x (horizontal) axis as long as it is in free fall.

The correct answer is (D). Coulombs Law is

The magnitude of the magnetic force is FB = qvB, so the acceleration of the particle has magnitude

The correct answer is (B). Assume at t=0, first drop starts to fall.
So, its distance from the rainspout, h1= 0.5 g t2
At t = 0.5 s, next drop starts to fall.
So, its distance from the rainspout, h2= 0.5 g (t - 0.5)2
Separation between them at any time t = h1-h2
= 0.5 g [t2- (t - 0.5)2]
= 0.25 g (2t - 0.5)
So, it increases in a linear manner.

Making simultaneous measurements of position and momentum is limited by the Uncertainty Principle, a quantum mechanical law.

The time interval from a point moving from its maximum displacement above y = 0 (equilibrium) to its maximum displacement below equilibrium is equal to one-half the period of the wave. In this case

The correct answer is (A). The tension in the rope increases as the angle decreases because the sum of the four forces leads to ΣF = 2T = Wt/sinθ. Note that as the angle becomes smaller, its sine also becomes smaller. This causes the tension in the line to increase drastically.

The correct answer is (B). The total resistance for a set of resistors in parallel is found by using the sum of the reciprocals. That is to do the following yielding the decimal solution Which is

The correct answer is (B). The voltage of the two batteries in series adds together, providing a voltage equivalent to their sum.

The baseball is still under the influence of Earth's gravity. Its acceleration throughout the entire flight is constant, equal to g downward.

The equation P = I2R gives

The correct answer is (C). The heat in the water and any heat added to the water is used by the system to melt the ice. This constitutes a phase change, too.

The velocity of an object undergoing uniform circular motion is always changing (because the direction is always changing), so A and B are eliminated. Furthermore, since the acceleration is centripetal, it must always point toward the center of the circle; so, as the object moves around the circle, the acceleration vector is also constantly changing direction. Since the acceleration changes, the answer must be E. Notice that for an object in uniform circular motion, both the velocity and the acceleration are changing because the directions of these vectors are always changing, even though their magnitudes stay the same.

If an object's speed is changing, it must be moving, so its displacement is changing. Since velocity, v, is speed plus direction, a change in speed automatically means a change in velocity. Now, since the velocity is changing, the linear momentum, p, must be changing also, since p = mv. Finally, because kinetic energy is equal to times the square of the speed, a changing speed implies a changing kinetic energy. The answer must be C. An object undergoing a change in speed may certainly be subject to a constant acceleration (gravitational acceleration, for example).

The correct answer is (B). The same number of charged bodies are still in the system, however, the redistribution of the charge has reduced the force the pith balls exert on one another.

The correct answer is (B). When the child jumps into his mother's arms, he pushes on the wagon as he jumps. The momentum the child gains when he jumps is passed on to the wagon, too. They both have the same momentum, but in opposite directions.The wagon must have a greater velocity since it has less mass.