Physics Relativity Level: Misc Level
What would be the speed of an observer be if a red (4.688 x10^14 Hz) traffic light apppeared green (5.555 x10^14 Hz) to the observer? (a) 4.445 x10^8 m/s
(b) 2.219 x 10^8 m/s
(c) 8.438 x 10^7 m/s
(d) 5.548 x 10 ^7 m/s
(e) 2.890 x 10 ^6 m/s
Physics Electromagnetic Waves Level: Misc Level
The amplitude of the elecric field component of an electromagnetic wave is increased from E to 4 E. What is the corresponding change in the intensity of the wave?
(a) The intensity is unchanged by the increase in E
(b) The intensity increases by a factor of 16
(c) The intensity increases by a factor of 4
(d) The intensity decreases by a factor of 4
(e) The intensity decreases by a factor of 16
Physics Alternating Current Level: Misc Level
When the frequency of an ac circuit is increased at constant coltage, the current increases and then decreases. Which combination of elements is most likely to comprise this circuit?
(a) resistors only
(b) inductors only
(c) capacitors only
(d) a combination of inductors and resistors
(e) a combination of inductors and capacitors
Physics Alternating Current Level: Misc Level
When the frequency of an ac circuit is decreased, the current in the circuit increases.Which combination of elements is most likely to comprise the circuit?
(a) resistors only
(b) inductors only
(c) capacitors only
(d) capacitors and resistors
(e) inductors and capacitors
Physics Alternating Current Level: Misc Level
A battery is used to drive a circuit. After a certain amount of time the current is zero amperes. When the same circuit is driven by an ac generator,the current is non-zero and alternates. Which combination of elements is most likely to comprise the circuit?
(a) resistors only
(b) inductors only
(c) capacitors only
(d) capacitors and resistors
(e) inductors and capacitors
Physics Waves And Oscillations Level: Misc Level
Two identical tuning forks are struck, then one is placed on a moving stage, constant speed away from the observer, and the other is left stationary. What would the observer hear?Explain.
Physics Properties Of Matter Level: Misc Level
A bar 2. 0 long is suspended horizontally from its ends by steel wires 1.0 long . The wires have radii of 1.0 mm. A mass of 20 kg is then attached 40 cm from one end of the bar. what is the difference in length between the wires?
Physics Properties Of Matter Level: Misc Level
A certain material has a density of (rho) and a tensile strenght of U. How long a rod of this material can be suspended from one end without breaking under its its own weight?What is this length in the case of aluminum? steel? ( assume the density of steel to be the same as that of iron)
Physics Electromagnetic Induction Level: Misc Level
An airplane with wingspan (tip to tip-of 70.om is flying horizontallly with a speed of 800 km/h towards north. The Earth,s magnetic field is 7 x 10^-5 T at this location., pointing towards theNorth, but with an angle of 40 degrees below the horizontal (ie. partially down toward the ground)
a) what voltage is induced between the plane,s wing tips?
b) which end (the left or the right will be positive?
Physics Waves And Oscillations Level: Misc Level
tension is maintained in a string. The observed wave speed is 24 m/s when the suspended mass is 3.0 kg. a) what is the mass per unit length of the string? B) what is the wave speed when the suspended mass is 2.0 kg?
Physics Waves And Oscillations Level: Misc Level
A 1.5 kg block at rest on a tabletop is attached to a horizontal spring having constant 19.6 N/m. the spring is initially unstretched.cpnstant 20.0 N horizontal force is applied to the object causing the string to stretch. A) determine the speed of the object causing the moved 0.3m from equilibrium if the surface between the block and tabletop is frictionless. b) answer part a) if the coefficient of kinetic friction between block and tabletop is 0.200.
Physics Work,Power & Energy Level: Misc Level
A 75 kg cross country .skier glides over snow.the coefficient of friction between skis and snow is 0.20.Assume all the snow beneath his skis is at 0 oc and that all the internal energy generated by friction is added to snow that sticks to his skis until melted. How far would he have to ski to melt 1.0 kg of snow?
Physics Work,Power & Energy Level: Misc Level
A siphon is a device that allows a fluid to seemingly defy gravity.The flow must be initiated by a partial vacuum in the tube,as in a drinking straw.a)show that the speed at which the water emerges from the siphon is given by v=sqrt (2gh). b) for what values of y will the siphon work?
Physics Properties Of Matter Level: Misc Level
A light spring of constant k=160 N/m rests vertically on the bottom of a large beaker of water.A 5.00 1g block of wood (density=650 1g/m^3) is connected to the spring, and the block-spring system is allowed to come to static equilibrium. What is the elongation (triangle)L of the spring?
Physics Work,Power & Energy Level: Misc Level
An object initially at rest breaks into two pieces as the result of an explosion. One piece (m2) has four times the kinetic energy of the other piece (m1). What is the ratio of the masses of the two pieces?
m1/m2= Which piece has the larger mass?The masses must be equal. The piece with the larger kinetic energy. The piece with the smaller kinetic energy.
