Physics Heat & Thermodynamics Level: Misc Level
The amount of heat per second conducted from the blood capillaries beneath the skin to the surface is 270 J/s. The energy is transferred a distance of 2.0x10-3 m through a body whose surface area is 1.5 m2.Assuming that the thermal conductivity is that of body fat, determine the temperature difference between the capillaries and the surface of the s %C
Physics Heat & Thermodynamics Level: Misc Level
The temperature in an electric oven is 163%C. The temperature at the outer surface in the kitchen is 54%C. The oven (surface area=1.5 m2) is insulated with material that has a thickness of 0.022 m and a thermal conductivity of 0.045 J/(s.m.%C).(a) How much energy is used to operate the oven for 7 hours?--J (b) At a price of $0.12 per kilowatt hour for electrical energy, what is the cost of operating the oven$--
Physics Heat & Thermodynamics Level: Misc Level
One end of a brass bar is maintained at 292%C, while the other end is kept at a constant but lower temperature. The cross-sectional area of the bar is 5.0 x 10-4 m2. Because of insulation, there is negligible heat loss through the sides of the bar. Heat flows through the bar, however, at the rate of 2.6 J/s. What is the temperature of the bar at a point 0.17 m from the hot end?---%C
Physics Current Electricity Level: Misc Level
Which one of the following situations results in a conventional electric current that flows westward?
(a) a beam of protons moves eastward?
(b) an electric dipole moves westward
(c) a beam of electrons moves westward
(d) a beam of electrons moves eastward
(e) a beam of neutral atoms moves westward
Physics Electrostatics Level: Misc Level
The effective area of each plate of a parallel plate capacitor is 2.4 ,m^2.The capacitor is filled with neoprene rubber (k=6.4). When a 3.0V potential difference exists across the plates of the capacitor, the capacitor stores 5.0uC of charge. Determine the plate separation of the capacitor.
(a) 7.2 x 10^-5 m
(b) 3.0 x 10^-4 m
(c) 1.7 x 10 ^-4 m
(d) 5.3 x 10^-4 m
(e) 8.2 x 10^-5 m
Physics Electrostatics Level: Misc Level
The magnitude of the charge on the plates of an isolated parallel plate capacitor is doubled. Which one of the following statements is true concerning the capacitance of this parallel- plate system?
(a) The capacitance is decreased to one half of its original value
(b) The capacitance is increased to twice it original value<--my answer
(c) The capacitance remains unchanged
(d) The capacitance depends on the electric field between the plates
(e) The capacitance depends on the potential difference across the plates
Physics Electrostatics Level: Misc Level
Which one of the following statements concerning electrostatic situations is false?
(a) E is zero everywhere inside a conductor
(b) Equipotential surfaces are always perpendicular to E
(c) It takes zero work to move a charge along an equipotential surface
(d) If V is constant throughout a region of space then E must be zero in that region
(e) No force component acts along the path of a charge as it moved along the equipotential surface<----my answer
Physics Electrostatics Level: Misc Level
If an electron,which has a charge of 1.60 x 10^-19C, is moved from rest at A to rest at B, what is the change in electric potential energy of the electron?
(a) +4.3 x 10^-15 J
(b) + 5.4 x 10^-15 J
(c) -2.1 x 10^-14 J
(d) -3.2 x 10^-14 J
(e) zero joules<-----my answer
Physics Modern Physics Level: Misc Level
X-rays of wavelength 10.0 pm are incident on a target. Find the wavelength of the x- rays scattered at (a)45.0% (b)90.0%.
Physics Modern Physics Level: Misc Level
If the shortest wavelength produced by an x-ray tube is 0.46 nm, what is the voltage applied to the tube?
Physics Modern Physics Level: Misc Level
The minimum energy required to remove an electron from a metal is 2.60 eV. What is the longest wavelength photon that can eject an electron from this metal?
Physics Force & Laws Of Motion Level: Misc Level
Sand from a stationary hopper falls on a mov-ing conveyor belt at the rate of 4.94 kg/s. The belt is supported by frictionless rollers and moves at 0.726 m/s un-der the action of a horizontal external force supplied by the motor that drives the belt.Find the frictional force exerted by the belt on the sand. Answer in units of N.
Physics Work,Power & Energy Level: Misc Level
A (n) 6.5 g bullet is fired into a (n) 1.8 kg ballistic pendulum. The bullet emerges from the block with a speed of 176 m/s, and the block rises to a maximum height of 8 cm.The acceleration of gravity is9. 8 m/s squared. Find the initial speed of the bullet. Answer in units of m/s.
Physics Force & Laws Of Motion Level: Misc Level
A rocket engine consumes 100 kg of fuel per second. If the exhaust speed is 4000 m/s, calculate the thrust on the roket. Answer in units of kN.
Physics Rotational Mechanics Level: Misc Level
Three point mass particles are located in a plane;3. 61 kg located at the origin, 5. 8121 kg at [(6.72 cm); (13.44 cm)], and 1. 7328 kg at [(18.2112 cm); (0 cm)].How far is the center of mass of the three particles from the origin?Answer in units of cm.
